![Appl. Sci. 2020, 10, 1803 2 of 41
use practical experience or follow an irrigation method to estimate manually the water needs of their
crops. Based on their estimations, the farmers decide whether to irrigate the fields. This conventional
approach has two significant drawbacks. First, irrigation requires daily observations, often made by
farmers. Manual observations are influenced by other factors such as the weather or the situation of
farmers. For example, a daily observation could be skipped if the farmer is sick. Second, the resource
shortage problem demands that farmers use water sparingly.
Context-aware systems (CASs) can overcome the above-mentioned situations. A CAS uses a
wireless sensor network (WSN) to monitor environmental phenomena and uses those measurements
for further processes. In a CAS, context refers to “any information that can characterize the situation of
an entity. An entity could be a person, a place or an object that is considered relevant to the interaction
between a user and an application, including the user and the application themselves” [1]. A CAS
has two contexts: a low-level context and a high-level context [2]. The low-level context contains
quantitative data. The high-level context contains qualitative data that synthesize a situation and ease
the decision. For example, the statement “soil moisture is 160 centibar (cbar)” presents a low-level
context; however, the statement “soil is dry” presents a high-level context.
The CAS has some peculiar characteristics. First, sensors in the system are heterogeneous. Each
type of phenomenon demands a different type of sensor. For example, in agriculture, pluviometers
measure rain quantity, and tensiometers measure soil moisture. Thus, the CAS should address
some data interoperability issues. Second, the system should have the capability to process the raw
measurement data and apply reason on them.
To address the above requirements, ontologies are adequate candidates. Some sensor ontologies
are provided by several institutes of standardization. Their main goal is to propose a shared data
schema that precisely describes measurements to ease their interpretations. These descriptions are
reusable by any machine and understandable by humans. They propose a data modeling design pattern
that is precise enough to answer any informational need. Thus, any sensor measurements described
by these ontologies may be reusable by several decision support systems (DSSs). The sensor network
becomes a data provider for several applications. For example, rain quantity measurements can be
used by irrigation decision systems and crop disease management systems. Reusing existing ontologies
enables the harmonization of sensor measurement descriptions. Moreover, those descriptions share
the same data model. Thus, they are easy to integrate in a global data schema. Furthermore, some
ontologies enable reasoning over data because they propose logical descriptions. In short, ontologies
used in context modeling can solve the heterogeneity issues of various sensor measurements and infer
the high-level context and decisions by applying rules. To the best of our knowledge, the proposed
work is the first to reuse two well-known ontologies: the new version of the Semantic Sensor Network
(SSN) [3] and Smart Appliances REFerence (SAREF) [4].
This paper presents the development method of a CAS that combines two engineering
methodologies: ontology and information systems. This method was used to build a smart irrigation
CAS that automates a manual irrigation method. This irrigation method, called IRRINOV®, was
developed by Arvalis (Arvalis is an applied agricultural research organization dedicated to arable
crops. It engages in many activities at 27 different local sites in France.) and its partners. The IRRINOV®
method is widely used in many regions in France. The development of the system also includes the
development of two new ontologies—the Context-Aware System Ontology (CASO) and Irrigation
ontology (IRRIG)—and a set of rules for reasoning. The two new ontologies reuse well-known
ontologies related to sensors and devices—SSN and SAREF. CASO specializes and extends SSN to
describe the processing of context. CASO implements a generic context model that can be specialized
to any observation of environmental phenomena. Using CASO simplifies the data processing and rule
generating by dividing them in several steps. IRRIG specializes CASO by implementing the IRRINOV®
method. The two ontologies model the sensor measurements and results of all measurement processing
(cleaning, aggregation, reasoning, etc.). The system uses a set of rules for reasoning. Each rule](https://image.slidesharecdn.com/5363100-250630162901-a1b5f338/85/Development-Experience-Of-A-Contextaware-System-For-Smart-Irrigation-Using-Caso-And-Irrig-Ontologies-Quangduy-Nguyen-6-320.jpg)
![Appl. Sci. 2020, 10, 1803 3 of 41
implements small inference steps. Thus, they are easy to understand, manage and correct. Finally, we
propose a complete DSS that supports farmers in making daily irrigation decisions.
The rest of this paper is organized as follows. Section 2 presents the state of the art of several smart
irrigation systems available in the research world. Section 3 introduces background information for
the cycle of processes implemented in a CAS and the IRRINOV® method. The next section describes
the development process of the complete system and the two ontologies. Section 5 provides an
example of the development presented in Section 4. Section 6 presents and compares the results after
implementing the system using real experimental data provided by Arvalis. Also, this section discusses
the limitations of the IRRINOV® method, the limitations of the Arvalis dataset and the limitations of
the DSS system. Finally, a brief conclusion sums up the system and presents the perspectives.
2. State of the Art
As mentioned in the introduction, an ontology is a shared data schema that provides a common
understanding of data descriptions. Data descriptions based on ontologies are reusable by any machine
and understandable by humans. Thus, we examined ontologies already used in irrigation decision
systems to reuse them as data modeling patterns to improve the results of our data modeling activity.
Several expert systems already exist that can determine whether a crop needs water. For example,
one expert system uses the common-KADS method to irrigate mango trees, as presented in [5]. Please
note that this expert system is not connected to any sensors or actuators. Its goal is to help farmers
decide when to irrigate. However, no information about the ontology publication is provided.
Semantic web technologies are already used in CASs dedicated to irrigation. For example, the
FIWARE platform that links Internet of Things (IoT) devices to the cloud has been used in several
different irrigation experiments [6]. The FIWARE cloud platform contains the SEPA SPARQL-based
engine, which represents information in an RDF format and provides SPARQL queries. To the best of
our knowledge, no information about the ontologies used in these experiments is available online.
The works of [7,8] present some ontologies dedicated to hilly citrus tree cultivation. One ontology
addresses the irrigation decision. The ontology stores the computations of relative soil moisture based
on the soil type and the crop growth stage. When the soil moisture reaches a given threshold, the
farmers receive an alert from the system. In this case, the ontology is not published; therefore, it is
impossible to reuse it.
To our point of view, the most successful CAS dedicated to irrigation is the one developed during
the PLANTS project [9]. This system is installed in a greenhouse. It uses several types of sensors to
observe raspberry plants. This system can control watering equipment to control irrigation in the four
zones of the greenhouse. The PLANTS ontology aims to describe e-entities and their interactions [9,10].
An e-entity is a virtual representation of a physical object that can be either a raspberry plant or
equipment. Every measurement is defined as the parameter of an e-entity. Sensor streams are not
aggregated. The last measurements are used to update a parameter. The rules are used to derive the
states of raspberry plants from various parameters. Watering equipment is controlled by the detection
of “drought stress” in a specific zone. Thus, the only part of the ontology that we want to reuse is the
plant state hierarchy. Unfortunately, this ontology is unavailable on the Web because it is the schema
of the facts-base implemented in the Jess inference engine.
To conclude, while several works focus on processing sensor streams and computing aggregations,
their results are not directly reusable, as our approach should handle the temporal and spatial
aggregation of sensor streams for the irrigation use case. Additionally, the ontologies mentioned
in previous works are either unavailable online or their domain is loosely related to our use case.
3. Background Information
This smart irrigation system is based on a CAS and the IRRINOV® method. First, the cycle of
processes implemented in a CAS provides an overview of the global system: its devices, its phases of](https://image.slidesharecdn.com/5363100-250630162901-a1b5f338/85/Development-Experience-Of-A-Contextaware-System-For-Smart-Irrigation-Using-Caso-And-Irrig-Ontologies-Quangduy-Nguyen-7-320.jpg)
![Appl. Sci. 2020, 10, 1803 4 of 41
processes and the transformation from data to context. Second, the IRRINOV® method specifies the
requirements of the system and the basic algorithm for making decisions.
3.1. Cycle of Processing Dedicated to CAS
In irrigation, a CAS has three specific components. First, a WSN plays the role of sensing and
monitoring the plot environment. Second, a DSS can (1) send notifications to farmers to support them
in their decision-making process and (2) automatically make decisions and control the watering system.
Third, watering devices are in charge of watering the soil in the field.
The CAS processes can be grouped and represented as a cycle of processes [11]. This cycle is
called the CAS life cycle. It is divided into four phases: (1) acquisition, (2) modeling, (3) analysis,
and (4) exploitation. Please note that this section improves our previous work about CAS life cycle
[12] by decreasing the number of phases. The exchange between two phases can consist of data, the
low-level context or the high-level context. The CAS life cycle for smart irrigation is depicted in Figure
1. The four phases of its life cycle are described as follows.
Exploitation
phase
Acquisition
phase
Modeling
phase
Analysis
phase
Data
Low-level
context
External
data
sources
Data
External
systems
Information
Data
High-level
context
Watering
device
Wireless Sensor
Network
Figure 1. Life cycle of a smart irrigation CAS.
• Acquisition phase focuses on how the system retrieves and processes measurements from sensor
devices and data from external data sources. The output of this phase are measurements and
related data derived after raw data cleaning processes.
• Modeling phase focuses on the data model and the integration of input data into the system.
The system is equipped with a storage service. The input data are organized with a common
data model to become the low-level context. As shown in Figure 1, the input of this phase is data
derived from the acquisition phase. The output of this phase is the low-level context. This paper
considers ontologies as a candidate for the data modeling process.
• Analysis phase focuses on the transformation from the low-level context into the high-level
context. The high-level context is an enrichment of the context with qualitative data. Such
data summarize the situation of entities and support the decision process. The system uses a
rules-based inference engine for the reasoning process. As shown in Figure 1, the input of this
phase is the low-level context. The output of this phase is the high-level context. This paper
considers Drools (https://www.drools.org/) as a candidate for the inference engine.
• Exploitation phase focuses on the use of the high-level context to distribute them to
corresponding agents, which can be other devices or users. The input of this phase is the
high-level context. The output of this phase can be human-readable content, a message to an
external system or a reaction of a watering device to the environment.](https://image.slidesharecdn.com/5363100-250630162901-a1b5f338/85/Development-Experience-Of-A-Contextaware-System-For-Smart-Irrigation-Using-Caso-And-Irrig-Ontologies-Quangduy-Nguyen-8-320.jpg)
![Appl. Sci. 2020, 10, 1803 5 of 41
3.2. IRRINOV® Method
This subsection presents the IRRINOV® (All versions of the IRRINOV® method are available
at http://www.irrinov.arvalisinstitutduvegetal.fr/irrinov.asp) method. This method, developed by
Arvalis and its partners, proposes a guide to make irrigation decisions based on measurements of
soil moisture sensors and pluviometers oriented to farmers. The method aims at answering the
following questions: (1) When should irrigation be started, or when should watering devices be
installed on the plot? (2) When should we start each watering cycle (“Watering cycle” is the action of
an irrigation system performing a watering activity on all the plots engaged in the system. “Watering
cycle duration” is the number of days between two consecutive waterings of the same plot.)? (3) When
should irrigation be stopped, or when should farmers withdraw the watering devices?
A set of decision tables and recommendations are provided by IRRINOV® method to allow
farmers to manage their irrigation system on a single plot. Numerous variants of the method are
proposed depending on the soil, plot and crop types. This work uses the IRRINOV® method for the
region Midi-Pyrénée, which is dedicated to maize crop plants on clay-limestone soil [13] and includes
the following measuring equipment:
• One IRRINOV® measuring station composed of six Watermark (https://www.irrometer.com/
sensors.html#wm) probes that measure the soil water tension (tensiometer). Three Watermark
probes should be placed at 30 cm depth in the soil, and the other three should be placed at 60 cm
depth in the soil. Figure 2 illustrates the prototype of the IRRINOV® station.
• One mobile pluviometer that measures the amount of water received by the crop during a
watering.
• One weather station with a pluviometer to measure the quantity of water received by the crop
during a rainfall.
Pluviometer
Monitor box
IRRINOV station
Soil sensor at 30cm depth
Soil sensor at 60cm depth
Figure 2. Prototype of the IRRINOV® station.
More information about IRRINOV® method is available at [12]. The goal of this section is to
illustrate the processing defined un previous section. The IRRINOV® method specifies the time needed
to install the devices on the plot. The IRRINOV® station and the mobile pluviometer should be placed
in the plot when the crop reaches growth stage V2 (V2, V7, R1, and R5 are the code names of maize
growth stages defined in [14]. They are respectively named “7 leaf”, “10 leaf”, “silking” and “dent
stage with 50% moisture” in the Arvalis growth stage classification.). The measurements can start two
or three days after installation. The Watermark probes are typically read once a week, but during dry
weather, farmers can check the probes more frequently, for example, one observation per day. Irrigation
should stop when the crop reaches the growth stage R5hg45. Please note that state R5 is defined in [14];
however, the state R5hg45 is defined in this project. This state means that the crops have moisture dents
equivalent to 45%. The IRRINOV® method specifies the constraints to validate the measurements
of Watermark probes. Those treatments are part of the acquisition phase. If the difference between
the probe measurements is above 30 cbar, then one of the probes is malfunctioning, and the farmer
should visit the field to correct the probe installation. The value read on a Watermark probe must
be multiplied by the correction coefficient, which is specific for each batch of probes. For example,](https://image.slidesharecdn.com/5363100-250630162901-a1b5f338/85/Development-Experience-Of-A-Contextaware-System-For-Smart-Irrigation-Using-Caso-And-Irrig-Ontologies-Quangduy-Nguyen-9-320.jpg)
![NO. XVIII.—PÆSTUM.[101]](https://image.slidesharecdn.com/5363100-250630162901-a1b5f338/85/Development-Experience-Of-A-Contextaware-System-For-Smart-Irrigation-Using-Caso-And-Irrig-Ontologies-Quangduy-Nguyen-32-320.jpg)
Development Experience Of A Contextaware System For Smart Irrigation Using Caso And Irrig Ontologies Quangduy Nguyen
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- 5. applied sciences Article Development Experience of a Context-Aware System for Smart Irrigation Using CASO and IRRIG Ontologies Quang-Duy Nguyen 1,*,† , Catherine Roussey 1,† , María Poveda-Villalón 3,† , Christophe de Vaulx 2 and Jean-Pierre Chanet 1 1 Université Clermont Auvergne, INRAE, UR TSCF, 63178 Aubière, France; catherine.roussey@inrae.fr (C.R.); jean-pierre.chanet@inrae.fr (J.-P.C.) 2 Limos, UMR 6158 Aubière, France; christophe.devaulx@isima.fr 3 Ontology Engineering Group, Universidad Politécnica de Madrid, 28040 Madrid, Spain; mpoveda@fi.upm.es * Correspondence: quang-duy.nguyen@inrae.fr † These authors contributed equally to this work. Received: 31 December 2019; Accepted: 21 February 2020; Published: 5 March 2020 Featured Application: This paper presents a smart irrigation context-aware system to be applied on an experimental farm in France. The experimental farm is an ecosystem for agricultural machines and digital information systems developed by an alliance of European organizations and institutes. Moreover, the two ontologies proposed by this paper, CASO and IRRIG, are open access and have the potential to be used by other applications such as smart buildings or smart cities. Abstract: The rapid development of information and communication technologies and wireless sensor networks has transformed agriculture practices. New tools and methods are used to support farmers in their activities. This paper presents a context-aware system that automates irrigation decisions based on sensor measurements. Automatic irrigation overcomes the water shortage problem, and automatic sensor measurements reduce the observational work of farmers. This paper focuses on a method for developing context-aware systems using ontologies. Ontologies are used to solve heterogeneity issues in sensor measurements. Their main goal is to propose a shared data schema that precisely describes measurements to ease their interpretations. These descriptions are reusable by any machine and understandable by humans. The context-aware system also contains a decision support system based on a rules inference engine. We propose two new ontologies: The Context-Aware System Ontology addresses the development of the context-aware system in general. The Irrigation ontology automates a manual irrigation method named IRRINOV®. These ontologies reuse well-known ontologies such as the Semantic Sensor Network (SSN) and Smart Appliance REFerence (SAREF). The decision support system uses a set of rules with ontologies to infer daily irrigation decisions for farmers. This project uses real experimental data to evaluate the implementation of the decision support system. Keywords: agriculture; smart irrigation; context-aware system; ontology; rules 1. Introduction In the agricultural domain, farmers need to observe natural phenomena to engage in appropriate activities on their fields. For example, in traditional irrigation, farmers go to their fields to examine the crop development stage and measure the soil moisture provided by probes in the soil. Then, they Appl. Sci. 2020, 10, 1803; doi:10.3390/app10051803 www.mdpi.com/journal/applsci
- 6. Appl. Sci. 2020, 10, 1803 2 of 41 use practical experience or follow an irrigation method to estimate manually the water needs of their crops. Based on their estimations, the farmers decide whether to irrigate the fields. This conventional approach has two significant drawbacks. First, irrigation requires daily observations, often made by farmers. Manual observations are influenced by other factors such as the weather or the situation of farmers. For example, a daily observation could be skipped if the farmer is sick. Second, the resource shortage problem demands that farmers use water sparingly. Context-aware systems (CASs) can overcome the above-mentioned situations. A CAS uses a wireless sensor network (WSN) to monitor environmental phenomena and uses those measurements for further processes. In a CAS, context refers to “any information that can characterize the situation of an entity. An entity could be a person, a place or an object that is considered relevant to the interaction between a user and an application, including the user and the application themselves” [1]. A CAS has two contexts: a low-level context and a high-level context [2]. The low-level context contains quantitative data. The high-level context contains qualitative data that synthesize a situation and ease the decision. For example, the statement “soil moisture is 160 centibar (cbar)” presents a low-level context; however, the statement “soil is dry” presents a high-level context. The CAS has some peculiar characteristics. First, sensors in the system are heterogeneous. Each type of phenomenon demands a different type of sensor. For example, in agriculture, pluviometers measure rain quantity, and tensiometers measure soil moisture. Thus, the CAS should address some data interoperability issues. Second, the system should have the capability to process the raw measurement data and apply reason on them. To address the above requirements, ontologies are adequate candidates. Some sensor ontologies are provided by several institutes of standardization. Their main goal is to propose a shared data schema that precisely describes measurements to ease their interpretations. These descriptions are reusable by any machine and understandable by humans. They propose a data modeling design pattern that is precise enough to answer any informational need. Thus, any sensor measurements described by these ontologies may be reusable by several decision support systems (DSSs). The sensor network becomes a data provider for several applications. For example, rain quantity measurements can be used by irrigation decision systems and crop disease management systems. Reusing existing ontologies enables the harmonization of sensor measurement descriptions. Moreover, those descriptions share the same data model. Thus, they are easy to integrate in a global data schema. Furthermore, some ontologies enable reasoning over data because they propose logical descriptions. In short, ontologies used in context modeling can solve the heterogeneity issues of various sensor measurements and infer the high-level context and decisions by applying rules. To the best of our knowledge, the proposed work is the first to reuse two well-known ontologies: the new version of the Semantic Sensor Network (SSN) [3] and Smart Appliances REFerence (SAREF) [4]. This paper presents the development method of a CAS that combines two engineering methodologies: ontology and information systems. This method was used to build a smart irrigation CAS that automates a manual irrigation method. This irrigation method, called IRRINOV®, was developed by Arvalis (Arvalis is an applied agricultural research organization dedicated to arable crops. It engages in many activities at 27 different local sites in France.) and its partners. The IRRINOV® method is widely used in many regions in France. The development of the system also includes the development of two new ontologies—the Context-Aware System Ontology (CASO) and Irrigation ontology (IRRIG)—and a set of rules for reasoning. The two new ontologies reuse well-known ontologies related to sensors and devices—SSN and SAREF. CASO specializes and extends SSN to describe the processing of context. CASO implements a generic context model that can be specialized to any observation of environmental phenomena. Using CASO simplifies the data processing and rule generating by dividing them in several steps. IRRIG specializes CASO by implementing the IRRINOV® method. The two ontologies model the sensor measurements and results of all measurement processing (cleaning, aggregation, reasoning, etc.). The system uses a set of rules for reasoning. Each rule
- 7. Appl. Sci. 2020, 10, 1803 3 of 41 implements small inference steps. Thus, they are easy to understand, manage and correct. Finally, we propose a complete DSS that supports farmers in making daily irrigation decisions. The rest of this paper is organized as follows. Section 2 presents the state of the art of several smart irrigation systems available in the research world. Section 3 introduces background information for the cycle of processes implemented in a CAS and the IRRINOV® method. The next section describes the development process of the complete system and the two ontologies. Section 5 provides an example of the development presented in Section 4. Section 6 presents and compares the results after implementing the system using real experimental data provided by Arvalis. Also, this section discusses the limitations of the IRRINOV® method, the limitations of the Arvalis dataset and the limitations of the DSS system. Finally, a brief conclusion sums up the system and presents the perspectives. 2. State of the Art As mentioned in the introduction, an ontology is a shared data schema that provides a common understanding of data descriptions. Data descriptions based on ontologies are reusable by any machine and understandable by humans. Thus, we examined ontologies already used in irrigation decision systems to reuse them as data modeling patterns to improve the results of our data modeling activity. Several expert systems already exist that can determine whether a crop needs water. For example, one expert system uses the common-KADS method to irrigate mango trees, as presented in [5]. Please note that this expert system is not connected to any sensors or actuators. Its goal is to help farmers decide when to irrigate. However, no information about the ontology publication is provided. Semantic web technologies are already used in CASs dedicated to irrigation. For example, the FIWARE platform that links Internet of Things (IoT) devices to the cloud has been used in several different irrigation experiments [6]. The FIWARE cloud platform contains the SEPA SPARQL-based engine, which represents information in an RDF format and provides SPARQL queries. To the best of our knowledge, no information about the ontologies used in these experiments is available online. The works of [7,8] present some ontologies dedicated to hilly citrus tree cultivation. One ontology addresses the irrigation decision. The ontology stores the computations of relative soil moisture based on the soil type and the crop growth stage. When the soil moisture reaches a given threshold, the farmers receive an alert from the system. In this case, the ontology is not published; therefore, it is impossible to reuse it. To our point of view, the most successful CAS dedicated to irrigation is the one developed during the PLANTS project [9]. This system is installed in a greenhouse. It uses several types of sensors to observe raspberry plants. This system can control watering equipment to control irrigation in the four zones of the greenhouse. The PLANTS ontology aims to describe e-entities and their interactions [9,10]. An e-entity is a virtual representation of a physical object that can be either a raspberry plant or equipment. Every measurement is defined as the parameter of an e-entity. Sensor streams are not aggregated. The last measurements are used to update a parameter. The rules are used to derive the states of raspberry plants from various parameters. Watering equipment is controlled by the detection of “drought stress” in a specific zone. Thus, the only part of the ontology that we want to reuse is the plant state hierarchy. Unfortunately, this ontology is unavailable on the Web because it is the schema of the facts-base implemented in the Jess inference engine. To conclude, while several works focus on processing sensor streams and computing aggregations, their results are not directly reusable, as our approach should handle the temporal and spatial aggregation of sensor streams for the irrigation use case. Additionally, the ontologies mentioned in previous works are either unavailable online or their domain is loosely related to our use case. 3. Background Information This smart irrigation system is based on a CAS and the IRRINOV® method. First, the cycle of processes implemented in a CAS provides an overview of the global system: its devices, its phases of
- 8. Appl. Sci. 2020, 10, 1803 4 of 41 processes and the transformation from data to context. Second, the IRRINOV® method specifies the requirements of the system and the basic algorithm for making decisions. 3.1. Cycle of Processing Dedicated to CAS In irrigation, a CAS has three specific components. First, a WSN plays the role of sensing and monitoring the plot environment. Second, a DSS can (1) send notifications to farmers to support them in their decision-making process and (2) automatically make decisions and control the watering system. Third, watering devices are in charge of watering the soil in the field. The CAS processes can be grouped and represented as a cycle of processes [11]. This cycle is called the CAS life cycle. It is divided into four phases: (1) acquisition, (2) modeling, (3) analysis, and (4) exploitation. Please note that this section improves our previous work about CAS life cycle [12] by decreasing the number of phases. The exchange between two phases can consist of data, the low-level context or the high-level context. The CAS life cycle for smart irrigation is depicted in Figure 1. The four phases of its life cycle are described as follows. Exploitation phase Acquisition phase Modeling phase Analysis phase Data Low-level context External data sources Data External systems Information Data High-level context Watering device Wireless Sensor Network Figure 1. Life cycle of a smart irrigation CAS. • Acquisition phase focuses on how the system retrieves and processes measurements from sensor devices and data from external data sources. The output of this phase are measurements and related data derived after raw data cleaning processes. • Modeling phase focuses on the data model and the integration of input data into the system. The system is equipped with a storage service. The input data are organized with a common data model to become the low-level context. As shown in Figure 1, the input of this phase is data derived from the acquisition phase. The output of this phase is the low-level context. This paper considers ontologies as a candidate for the data modeling process. • Analysis phase focuses on the transformation from the low-level context into the high-level context. The high-level context is an enrichment of the context with qualitative data. Such data summarize the situation of entities and support the decision process. The system uses a rules-based inference engine for the reasoning process. As shown in Figure 1, the input of this phase is the low-level context. The output of this phase is the high-level context. This paper considers Drools (https://www.drools.org/) as a candidate for the inference engine. • Exploitation phase focuses on the use of the high-level context to distribute them to corresponding agents, which can be other devices or users. The input of this phase is the high-level context. The output of this phase can be human-readable content, a message to an external system or a reaction of a watering device to the environment.
- 9. Appl. Sci. 2020, 10, 1803 5 of 41 3.2. IRRINOV® Method This subsection presents the IRRINOV® (All versions of the IRRINOV® method are available at http://www.irrinov.arvalisinstitutduvegetal.fr/irrinov.asp) method. This method, developed by Arvalis and its partners, proposes a guide to make irrigation decisions based on measurements of soil moisture sensors and pluviometers oriented to farmers. The method aims at answering the following questions: (1) When should irrigation be started, or when should watering devices be installed on the plot? (2) When should we start each watering cycle (“Watering cycle” is the action of an irrigation system performing a watering activity on all the plots engaged in the system. “Watering cycle duration” is the number of days between two consecutive waterings of the same plot.)? (3) When should irrigation be stopped, or when should farmers withdraw the watering devices? A set of decision tables and recommendations are provided by IRRINOV® method to allow farmers to manage their irrigation system on a single plot. Numerous variants of the method are proposed depending on the soil, plot and crop types. This work uses the IRRINOV® method for the region Midi-Pyrénée, which is dedicated to maize crop plants on clay-limestone soil [13] and includes the following measuring equipment: • One IRRINOV® measuring station composed of six Watermark (https://www.irrometer.com/ sensors.html#wm) probes that measure the soil water tension (tensiometer). Three Watermark probes should be placed at 30 cm depth in the soil, and the other three should be placed at 60 cm depth in the soil. Figure 2 illustrates the prototype of the IRRINOV® station. • One mobile pluviometer that measures the amount of water received by the crop during a watering. • One weather station with a pluviometer to measure the quantity of water received by the crop during a rainfall. Pluviometer Monitor box IRRINOV station Soil sensor at 30cm depth Soil sensor at 60cm depth Figure 2. Prototype of the IRRINOV® station. More information about IRRINOV® method is available at [12]. The goal of this section is to illustrate the processing defined un previous section. The IRRINOV® method specifies the time needed to install the devices on the plot. The IRRINOV® station and the mobile pluviometer should be placed in the plot when the crop reaches growth stage V2 (V2, V7, R1, and R5 are the code names of maize growth stages defined in [14]. They are respectively named “7 leaf”, “10 leaf”, “silking” and “dent stage with 50% moisture” in the Arvalis growth stage classification.). The measurements can start two or three days after installation. The Watermark probes are typically read once a week, but during dry weather, farmers can check the probes more frequently, for example, one observation per day. Irrigation should stop when the crop reaches the growth stage R5hg45. Please note that state R5 is defined in [14]; however, the state R5hg45 is defined in this project. This state means that the crops have moisture dents equivalent to 45%. The IRRINOV® method specifies the constraints to validate the measurements of Watermark probes. Those treatments are part of the acquisition phase. If the difference between the probe measurements is above 30 cbar, then one of the probes is malfunctioning, and the farmer should visit the field to correct the probe installation. The value read on a Watermark probe must be multiplied by the correction coefficient, which is specific for each batch of probes. For example,
- 10. Other documents randomly have different content
- 11. of Haroun, completely silenced him.” Farther on, speaking of the antiquities of Wady Mousa, the same traveller says, “Of these I regret that I am not able to give a very complete account. I well knew the character of the people around me. I was without protection in the midst of a desert, where no traveller had ever before been seen; and a close examination of these works of the infidels, as they are called, would have excited suspicions that I was a magician in search of treasures. I should at least have been detained, and prevented from prosecuting my journey to Egypt, and in all probability should have been stripped of the little money which I possessed, and, what was infinitely more valuable to me, of my journal-book. Future travellers may visit the spot under the protection of an armed force; the inhabitants will become more accustomed to the researches of strangers, and the antiquities of Wady Mousa will then be found to rank amongst the most curious remains of ancient art.” We shall now give some account of the travels of Mr. Banks, and the party by whom he was accompanied.93 Having quitted the tents of the Bedouins, with whom they had sojourned for a few days, they passed into the valley of Ellasar, where they noticed some relics of antiquity, which they conjectured were of Roman origin. Here they rested with a tribe of Arabs. The next day they pursued their journey, partly over a road paved with lava, and which, by its appearance, was evidently a Roman work, and stopped that evening at Shuback, a fortress in a commanding situation; but incapable, by decay, of any effectual defence against European tactics. In the neighbourhood of this place they encountered some difficulties from the Arabs, but which, by their spirit and firmness, they overcame, and proceeded unmolested till they reached the tents of a chieftain called Eben Raschib, who took them under his protection. This encampment was situated on the edge of a precipice, from which they had a magnificent view of Mount Gebel- Nebe-Haroun, the hill of the prophet Aaron (Mount Hor); and a distant prospect of Gebel-Tour (Mount Sinai), was also pointed out to
- 12. them. In the fore-ground, on the plain below, they saw the tents of the hostile Arabs, who were determined to oppose their passage to Wady Mousa, the ruins of which were also in sight. Perceiving themselves thus as it were waylaid, they sent a messenger to the chief, requesting permission to pass; but he returned for answer, that they should neither cross his lands, nor taste his water. They were in fact in the land of Edom, to the king of which Moses sent messengers from Kadish. “Let us pass,” said he, “I pray thee, through thy country: we will not pass through the fields, or through the vineyards; neither will we drink of the waters of the well: we will go by the king’s highway; we will not turn to the right hand nor to the left, until we have passed thy borders.” But Edom said unto him, “Thou shalt not pass by me, lest I come out against thee with the sword.”—Numbers xx. 17, 18. The travellers, after some captious negotiation, at last obtained permission to pass; but not to drink the waters. They did not, however, very faithfully observe this stipulation; for on reaching the borders of a clear bright sparkling rivulet, their horse would taste the cooling freshness of its waters; and Eben Raschib, their protector, insisted also that the horses should be gratified. On crossing this stream they entered on the wonders of Wady Mousa. The first object that attracted their attention was a mausoleum, at the entrance of which stood two colossal animals; but whether lions or sphinxes they could not ascertain, as they were much defaced and mutilated. They then, advancing towards the principal ruins, entered a narrow pass, varying from fifteen to twenty feet in width, overhung by precipices, which rose to the general height of two hundred, sometimes reaching five hundred feet, and darkening the path by their projecting ledges. In some places niches were sculptured in the sides of this stupendous gallery, and here and there rude masses stood forward, that bore a remote and mysterious resemblance to the figures of living things, but over which, time and oblivion had drawn an inscrutable and everlasting veil. About a mile within this pass, they rode under an arch, which
- 13. connected the two sides together; and they noticed several earthen pipes, which had formerly distributed water. Having continued to explore the gloomy windings of this awful corridor for about two miles, the front of a superb temple burst on their view. A statue of Victory, with wings, filled the centre of an aperture in the upper part, and groups of colossal figures, representing a centaur, and a young man, stood on each side of the lofty portico. This magnificent structure is entirely excavated from the solid rock, and preserved from the ravages of the weather by the projections of the overhanging precipices. About three hundred yards beyond this temple, they met with other astonishing excavations; and, on reaching the termination of the rock on their left, they found an amphitheatre, which had also been excavated, with the exception of the proscenium; and this had fallen into ruins. On all sides the rocks were hollowed into innumerable chambers and sepulchres; and a silent waste of desolated palaces, and the remains of constructed edifices, filled the area to which the pass led. Since this, Captains Irby and Mangles, who accompanied Mr. Banks, have published an account of their journey:—“Our defile brought us directly down into the valley of Wady Mousa, whose name had become so familiar to us. It is, at the point where we entered it, a stony but cultivated valley, of moderate size, without much character or beauty, running in a direction from east to west. A lesser hollow, sloping down to it from the southward, meets it at an angle. At the upper end of the latter valley is the village seen over stages of hanging fruit-grounds, which are watered by a spring. * * Some hundred yards below this spring begin the outskirts of the vast necropolis of Petra. * * As we advanced, the natural features of the defile grew more and more imposing at every step, and the excavations and sculpture more frequent on both sides, till it presented at last a continued street of tombs, beyond which the rocks, gradually approaching each other, seemed all at once to close without any outlet. There is, however, one frightful chasm for the passage of the stream, which furnishes, as it did anciently, the only avenue to Petra on this side (the eastern).
- 14. “It is impossible,” continues Captain Irby, “to conceive any thing more awful and sublime than the eastern approach to Petra. The width is not more than just sufficient for the passage of two horsemen abreast; the sides are in all parts perpendicular, varying from four hundred to seven hundred feet in height; and they often overhang to such a degree, that, without their absolutely meeting, the sky is intercepted, and completely shut out for one hundred yards together, and there is little more light than in a cavern.” This half subterranean passage is more than two miles in length, and retains throughout the same extraordinary character. “After passing the Khasne, the defile becomes contracted again for three hundred yards, when suddenly the ruins of the city burst on the view in their full grandeur, shut in on the opposite side by barren craggy precipices, from which numerous ravines and valleys, like those we had passed, branch out in all directions. (All of these ravines, however, that were explored, were found to terminate in a wall of rock, admitting of no passage outwards or inwards.) The sides of the mountains, covered with an endless variety of excavated tombs and private dwellings, presented altogether the most singular scene we ever beheld. We must despair to give the reader an idea of the peculiar effect of the rocks, tinted with most extraordinary hues, whose summits present us with Nature in her most savage and romantic form; whilst their bases are worked out in all the symmetry and regularity of art, with colonnades and pediments, and ranges of corridors adhering to the perpendicular surface.” The next party that visited Petra were Messrs. Laborde and Linant. After traversing Wada Araba, they entered the Wady Mousa, the “mysterious valley of Petra.” Laborde confesses that, notwithstanding the perfect good feeling which existed between the travellers and their conductors, he felt an indefinable kind of fear that the grand object of their journey—the minute investigation of Petra—might, after all, be defeated. The “Fellahs of Wady Mousa” were yet to be reconciled to their plan of operations.
- 15. It is a common belief amongst the Arabs, that immense treasures are buried beneath the ruins that strew the rocky desert of Idumea; and it is, of course, a natural inference, that the object of Europeans in visiting the country is, by magic or superior craft, to obtain access to those treasures, the possession of which belongs to the lords of the soil. But in drawing near to the city, a danger, says M. Laborde, on which the travellers had not reckoned, proved a cause of their security. The plague had been brought from the shores of the Mediterranean into the secluded Wady Mousa, and the Fellahs had fled from its violence. The travellers, during their inspection of the city, were comparatively free from annoyance: but they would have staid longer if their Arab conductors, who were afraid of the plague, had not teased them to return; and the fact of their residence in Petra was beginning to spread. Messrs. Laborde and Linant arrived in Petra from the south; and on reaching a point from which they could see the extent of the town, they were struck with amazement at the immense mass of ruins strewed around, and the extensive circle of rocks inclosing the place, pierced with an innumerable quantity of excavations. In fact, words are inadequate to convey a clear idea of the ruins of Petra. In Laborde’s plan of Petra, the town is exhibited as completely encircled by huge rocks. These rocks are excavated in every variety of form. The only entrance to the town is from the south-west, by the windings of a narrow ravine, through which flows the river, or rather stream, of Wady Mousa94. “We wound round a peak,” says M. Laborde, “surmounted by a single tree. The view from this point exhibited a vast frightful desert; a chaotic sea, the waves of which were petrified. Following the beaten road, we saw before us Mount Hor, crowned by the tomb of the prophet, if we are to credit the ancient tradition, preserved by the people of that country. Several large and ruinous excavations, which are seen in the way, may arrest the attention of a traveller who is interested by such objects, and has no notion of those, still concealed from his view by the curtain of rocks which extends
- 16. before him; but at length the rock leads him to the heights above one more ravine; whence he discovers within his horizon the most singular spectacle, the most enchanting picture, which Nature has wrought in her grandest mood of creation; which men, influenced by the vainest dreams of ambition, have yet bequeathed to the generations that were to follow them. At Palmyra, Nature renders the works of man insignificant by her own immensity and her boundless horizon, within which some hundreds of columns seem entirely lost. Here, on the contrary, she seems delighted to set, in her most noble frame-work, his productions, which aspire, and not unsuccessfully, to harmonize with her own majestic, yet fantastic, appearance. The spectator hesitates for a moment, as to which of the two he is the more impelled to admire; whether he is to accord the preference to Nature, who invites his attention to her matchless girdle of rocks, wondrous as well for their colour as their forms; or to the men who feared not to mingle the works of their genius with such splendid efforts of creative power.” We now give an abstract of what has been written of this city, mainly taken from a very intelligent periodical journal, published at Edinburgh (Chambers’s Journal). Nearly at the spot where the defile opens into the site of the city, one excavation in the site of the pass arrests the attention of the traveller. This is a vast circular theatre hewn out of the solid rock, consisting of thirty-three seats of stone sloping upwards, and surmounted, and in some degree sheltered, by the rocks above. The countless tombs in the immediate vicinity of this ruined edifice led M. Laborde to remark on the extraordinary taste of the people of Petra, in selecting a place of amusement, encircled on all sides by the mansions and memorials of death! It is unnecessary to enter into a minute description of the excavated tombs and sepulchres, studding the rocky walls around Petra. The basis of the architecture, in almost all cases, is Grecian, mingled with Roman; though in many instances a style is apparent, which must be regarded as Egyptian, or rather the native style of Petra. Many of the
- 17. chambers within the tombs are so immense, that their real character might be doubted; were it not for the recesses they contain, destined, it is plain, for the reception of bodies. How enormous must have been the labour and expense, necessary for the excavation of these sepulchres, some of which are large enough to stable the horses of a whole tribe of Arabs! It is impossible to conceive that such resting-places could have been appropriated to any other persons than rulers or rich men, and great, indeed, as Mr. Burckhardt remarks, “must have been the opulence of a city, which could dedicate such monuments to the memory of its rulers.” Some of the finest mausoleums, as we have already seen, are not in the main valley, but in the ravines leading from it, where their multiplicity is beyond conception. In a ravine on the north-west, M. Laborde beheld one, called by the natives El-Deir, or the Convent, of much larger dimensions than the Khasne, and, like it, sculptured out of the rock, though not in a style so perfect. As the visitor advances into the area, he beholds in front of him one of the most splendid and beautiful objects in or around Petra, and what may justly be called one of the wonders of antiquity. This is the front of a great temple, nearly sixty-five feet in height, excavated from the solid rock, and embellished with the richest architectural decorations, all in the finest state of preservation. Six pillars, thirty- five feet high, with Corinthian capitals, support an ornamented pediment, above which stand six smaller pillars, the centre pair crowned by a vase, and surrounded by statues and other ornaments. Mere description can do no justice to this building. Near it stands a magnificent triumphal arch. This temple is termed by the Arabs “Khasne Pharaon,”—Pharaoh’s treasure; from their supposition that here are hidden those stores which they have vainly sought for elsewhere. In the sarcastic words of M. Laborde, “It was quite in accordance with their character, after having fruitlessly spoiled the monuments inclosed in the tombs, to seek the spot where the constructor of such magnificent edifices had deposited his treasure. That spot they supposed they had found at last—it was the urn which may be distinguished on the top of the
- 18. monument. This must contain all the riches of the great king;—but, unhappily, it is out of their reach, and only taunts their desire. Consequently, each time that they pass through the ravine, they stop an instant, fire at the urn, and endeavour to break it, in the hope of bringing it down and securing the treasure. Their efforts are fruitless; and they retire murmuring against the king of Giants, who has so adroitly placed his treasure 120 feet above their reach.” The temple is hewn in an enormous and compact block of freestone, which is lightly coloured with oxide of iron. Its high state of preservation is owing to the shelter which the surrounding rocks afford it against the wind, and also in preserving the roof from the rain. The only traces of deterioration are in the statues at the base of the column, which has been produced by the humidity undermining the parts most in relief, or nearest to the ground. To the same cause may be attributed the fall of one of the columns which was attached to the front. Had the structure been built instead of being hewn, the fall of this column would have dragged down the entire building. As it is, it merely occasions a void, which does not destroy the effect of the whole. “It has even been useful,” says M. Laborde, “in so far as it enabled us, by taking its dimensions, to ascertain the probable height of the temple, which it would otherwise have been impossible to do with precision.” He calls the temple “one of the wonders of antiquity,” and apologises for the expression in the following manner:—“We are apt, doubtless, to charge the traveller with exaggeration who endeavours, by high- sounding eulogiums, to enhance the merit of his fatigues, or the value of his labours: but here, at least, plates designed with care will establish the truth of a description which might otherwise appear extravagant.” The interior of the temple does not fulfil the expectations, created by the magnificence of the exterior. Several steps conduct to a room, the door of which is perceived under the peristyle. “Although the chamber is hewn regularly, and is in good proportion, the walls are rough, its doors lead to nothing, and the entire appears to have been abandoned while the work was yet in progress. There are two
- 19. lateral chambers, one of which is irregular, and the other presents two apertures, which seem to have been hewn for two coffins.” Captain Irby speaks of this temple in the following manner: “The position is one of the most beautiful that could be imagined for the front of a great temple, the richness and exquisite finish of whose decorations offer a most remarkable contrast to the savage scenery that surrounds it. It is of a very lofty proportion, the elevation comprising two stories. The taste is not exactly to be commended; but many of the details and ornaments, and the size and proportion of the great doorway especially, to which there are five steps of ascent from the portico, are very noble. No part is built, the whole being purely a work of excavation; and its minutest embellishments, wherever the hand of man has not purposely effaced and obliterated them, are so perfect, that it may be doubted whether any work of the ancients, excepting, perhaps, some on the banks of the Nile, have come down to our time so little injured by the lapse of ages. There is, in fact, scarcely a building of forty years’ standing in England so well preserved in the greater part of its architectural decorations. Of the larger members of the architecture nothing is deficient, excepting a single column of the portico; the statues are numerous and colossal.” The brook of Wady Mousa, after leaving the eastern defile by which it entered, passes directly across the valley, and makes its exit by a rocky ravine on the west, almost impassable by the foot of man. On the banks of this stream are situated the principal ruins of the city. There, at least, are found those in chief preservation—for, properly speaking, the whole valley may be said to be covered with ruins. The remains of paved-ways, bridges, and other structures, may still be seen among the other ruins of the valley. Not the least interesting object, observable in the vale, is the aqueduct which is continued from the eastern approach along the face of the rocks constituting the eastern wall of this city. This aqueduct is partly hewn and partly built, and is yet in a very perfect condition.
- 20. The only inscriptions, hitherto discovered at Petra, are two which M. Laborde met with on tombs. One of these, in Greek characters, was so much mutilated as to be unreadable, and the other, a Latin one, notified that a certain Roman consul died at Petra, when governor of Arabia. The only living being found residing in the immediate neighbourhood of the ruins, with the exception of the reptiles that infest the excavations, was a decrepit old man, who had lived for forty years on the top of Mount Hor, an eminence at the west of Petra, where a tomb, said to be that of Aaron, is seen. The wandering Arabs, who revere the Jewish traditions, hold this place as sacred, and support its old guardian by occasional pilgrimages and contributions95. For want of space we must here close our account; referring for a more enlarged knowledge of this celebrated “city of the desert,” to the travels of Burckhardt, Captains Irby and Mangles, and MM. Laborde and Linant. The following references lead to some of the passages, in which the fate of this city was foretold by the sacred writers96. “I will stretch out mine hand upon Edom, and will cut off man and beast from it, and I will make it desolate from Teman; and they of Dedan shall fall by the sword. And I will lay my vengeance upon Edom by the hand of my people Israel, and they shall do in Edom according to mine anger, and according to my fury, and they shall know my vengeance, saith the Lord God.”—Ezekiel, xxv. 13, 14. “Say unto it, thus saith the Lord God, behold, O Mount Seir, I am against thee, and I will stretch out mine hand against thee, and I will make thee most desolate, I will lay thy cities waste, and thou shalt be desolate, and thou shalt know that I am the Lord. Because thou hast had a perpetual hatred, and hast shed the blood of the children of Israel, by the force of the sword, in the time of their calamity.”—Ezekiel, xxxv. 3, 4. “The cormorant and the bittern shall possess it, the owl also and the raven shall dwell in it, and he shall stretch out upon it the line of confusion, and the stones of emptiness. The thorns shall come up in her palaces, nettles and brambles in the fortresses thereof, and it shall be an habitation of dragons, and a court for owls.”—Isaiah, xxxiv. 11, 13.
- 21. “And Edom shall be a desolation; every one, that goeth by it, shall be astonished, and shall hiss at the plagues thereof.”—Jeremiah, xlix. 17. “And the house of Jacob shall be a fire, and the house of Joseph a flame, and the house of Esau for stubble, and they shall kindle in them, and devour them, and there shall not be any remaining of the house of Esau.”—Obadiah, 18.
- 22. NO. XVI.—PHIGALIA. This was a town of Arcadia, called after Phigalus. Bacchus and Diana had each a temple there, and the public places were adorned with the statues of illustrious natives. “In the forum,” says Anacharsis, “is a statue which might serve for the history of the arts. The feet are almost joined, and the pendant hands are fastened close to the sides and thighs; for in this manner were statues formerly sculptured in Greece, and thus they are still in Egypt. It was erected for the athlete Arrhacion, who gained one of the prizes in the 52nd, 53rd, and 54th Olympiads. We may hence conclude that, two centuries before our time, many statuaries still servilely followed the Egyptian taste.” This town was situated on a high and craggy rock, near Megalopolis. Being the key, as it were, of Arcadia, the Lacedemonians laid siege to it and took it 659 b. c. In order to regain the city, the inhabitants consulted the oracle of Delphos, who directed them to select one hundred men from Orestasium to assist them. These brave persons perished; but the Orestasians, in concert with the Phigalians, attacked their enemies and routed them. The Phigalians afterwards erected a monument in honour of the one hundred men who had fallen. There was one temple dedicated to Diana Conservatrix, in which was her statue, and another dedicated to Apollo the Deliverer. Chandler relates, that M. Joachim Bocher, an architect of Paris, was desirous of examining a building near Caritena. He was still remote from that place, when he perceived a ruin, two hours from Verrizza, which prevented him from going further. This ruin stands on an eminence, sheltered by lofty mountains. The temple, it is supposed, was that of Apollo Epicurius, near Phigalia. It was of the Doric order, and had six columns in front. The number which ranged round the
- 23. cella was thirty-eight. Two at the angles are fallen; the rest are entire, in good preservation, and support their architraves. Within them lies a confused heap. The stone inclines to grey, with reddish veins. To its beauty is added great precision in the workmanship. These remains had their effect, striking equally the mind and the eye of the beholder. The walls of Phigalia alone remain; they were flanked with towers, both square and circular. One gate towards the east is yet covered by blocks, which approach each other like the underside of a staircase. There has been a temple, of fine limestone, of the Doric order, on which is an inscription. Pausanias describes Phigalia as surrounded by mountains, of which one named Cotylium was distant about forty stadia, or five miles. The temple of Apollo stood on this, at a place called Bassæ. Under the ruins of this temple, the Baron Von Stachelberg discovered, in 1812, some curious bas-reliefs, which are now in the British Museum. They were executed in the time of Pericles, the temple having been built by Ictinus, the architect of the Parthenon. These bas-reliefs, representing the battle of the Centaurs and Lapithæ, and the combat between the Greeks and Amazons, composed the frieze in the interior of the cella, in the temple of Apollo the Deliverer. The battle of the Centaurs and Lapithæ is sculptured on eleven slabs of marble; that of the Greeks and Amazons occupies twelve. Besides these there are other fragments from the same temple:—1. A fragment of a Doric capital of one of the columns of the peristyle. 2. A fragment of an Ionic temple of one of the columns of the cella. 3. Two fragments of the tiles, which surmounted the pediments, and formed the superior moulding. 4. Fragments of metopes, found in the porticos. The following observations lately appeared in the Times newspaper: —“In the saloon of the British Museum are the celebrated bas- reliefs, found at Mount Cobylus, near the ancient city of Phigalia, in
- 24. Arcadia. They represent the battles of the Greeks and Amazons, and those of Theseus and the Lapithæ against the Centaurs. According to Pausanias, they were the work of Ictinus, a contemporary of Phidias. The grandeur of conception displayed in their composition, the variety of attitude and action shown, is not surpassed by those in the Elgin saloon, though their execution may be inferior. The combat of the Greeks and Amazons occupies twelve slabs of marble, and that of the Centaurs eleven. Both the history of the Amazons and the battle, here represented, are obscure. The origin of the name is derived from two words, ‘Ama’ or ‘Ma,’ which in all old languages signifies ‘mother’—its ubiquity is proof of its antiquity— and the ancient name of the sun, as found in the Temple of Heliopolis, in Egypt, is ‘On,’ ‘Ton,’ or ‘Zoan;’ but that any nation of Amazons, in the vulgar acceptation of the word, ever existed, is more than problematical. Faber says that those nations, who worshipped the female principle of the world, such as the Iberians, the Cimmerians, the Mootæ, the Atalantians of Mauritania, and the Ionians, were Amazons, and a celebrated invasion of Attica by them is mentioned. We are told that Eumolphus, an Egyptian, was the leader; and Pausanias mentions an Attic victory or trophy, called an Amazonium, erected to their manes. According to Arrian, the Queen of the Amazons, on the borders of the Caspian Sea, sent ambassadors with defiance to Alexander. In the time of Pompey, they were still supposed to exist; and Dion Cassius says, that in the Mithridatic war buskins and boots were found by the Roman soldiers, undoubtedly Amazonian. The worship of the male and female deities in Greece caused peace between the sects, and the origin of their quarrel and their name was forgotten in Europe. In Asia the Persians and the Jews seem still to have formed an exception. Cambyses, in his invasion, destroyed in Egypt everything connected with the female worship; he overturned the sphinxes, but he left the obelisks untouched. The scene of the combat, depicted on these tablets, is drawn with great force and spirit: some of the Amazons have long tunics, others short vestments, only reaching to the knee; one on horseback has trousers, and loose sleeves reaching to the wrist; on the head of some is the Archaic helmet, and those without have the
- 25. hair fastened in a knot on the top; they all but one wear boots, which reach to the knees; their robes are fastened with a zone; some have two belts crossed between the breasts; their arms are swords, and the double-headed Scythian battle-axe, as also spears, bows, and arrows. None of these last are preserved, they being probably of bronze, as the holes remain, and added afterwards, as was the custom with ancient sculpture; the shields are small, and of the lunar form, opening at top. The Athenian warriors have cloaks, or tunics, fastened round the neck, and tightened about the waist by a belt; it reaches no lower than the knee; the right arm is bare. In one group a fierce warrior has seized a mounted Amazon by the hair; he is dragging her from the horse, which is rearing. The action of the female figure is very fine: she firmly maintains her seat, till relieved by another; who, with uplifted axe and shield to protect her from the flying arrows, shall have brained her antagonist. The 18th slab has five figures and two horses; in one the horse has fallen, and an Athenian warrior has his right hand fixed on the throat of the Amazon, while, with the other hand, he has grasped her foot, and drags her, who seems to have lost all recollection, from the horse’s back. The position of the centre figure is very fine: he is within the guard of the shield of the Amazon, and is striking a deadly blow with his hand, in which has been a sword. In another group an Athenian has fallen; he rests on his left hand, and extends his right in supplication to the female warriors who surround him, and is in the act of surrendering, while behind him an Amazon is striking him with her battle-axe. In the sculptures of the Lapithæ and Centaurs all the warriors, with the exception of Theseus, are armed with swords, who, as an imitator of Hercules, has a club. The shields are large and circular; they have a broad border round the circumference, and resemble those of the Ephibi of Athens. Of the helmets there are four kinds—one which fits the head closely, without either crest or vizor; another with a crest, and one with guards for the ears, and a fourth with a pointed vizor. In one of the sculptures Theseus is seen attacking a Centaur; he has the head of the monster under his left arm, and with the right, which probably held a club of bronze, as the hole remains, he is destroying him. He appears to have arrived just
- 26. in time to save Hippodomia, whom the Centaur has disrobed, and who is clinging to the statue of Diana. From the tiara behind, and the lion’s skin, this figure is supposed to be Theseus; the Centaur is Eurytion; a female figure is also seen pleading on her behalf, and, in the distance, a Goddess is hastening in a car drawn by stags to the rescue; this probably is Diana, as the temple was dedicated to Apollo.” The city of Phigalia is now become a mere village, known by the name of Paolitza97.
- 27. NO. XVII.—PLATÆA. This city has long been famous; for it was in a plain near to it that was fought the celebrated battle between the Greeks and Persians98. On the evening previous to the engagement, the Grecians held a council of war, in which it was resolved, that they should decamp from the place they were in, and march to another more conveniently situated for water. Night being come on, and the officers endeavouring at the head of their corps to make more haste than ordinary to the camp marked out for them, great confusion happened among the troops, some going one way and some another, without observing any order or regularity in their march. At last they halted near the little city of Platæa. On the first news of the Grecians being decamped, Mardonius drew his army into order of battle, and pursued them with hideous shouting and bawling of his barbarian forces, who thought they were advancing not so much in order of battle, as to strip and plunder a flying enemy; and their general likewise, making himself sure of victory, proudly insulted Artabazus; reproaching him with his fearful and cowardly prudence, and with the false notion, he had conceived of the Lacedæmonians, who never fled, as he pretended, before an enemy; whereas here was an instance of the contrary. But the general found quickly this was no false or ill-grounded notion. He happened to fall in with the Lacedæmonians, who were alone and separated from the body of the Grecian army, to the number of fifty thousand men, together with three thousand of the Tegeatæ. The encounter was exceedingly fierce and resolute on both sides; the men fought with the courage of lions, and the barbarians perceived that they had to do with soldiers, who were determined to conquer or die on the field. The Athenian troops, to whom Pausanias sent an officer, were already upon their march to their aid; but the Greeks who had taken part with the Persians, to the number of fifty
- 28. thousand men, went out to meet them on their way, and hindered them from proceeding any farther. Aristides, with his little body of men, bore up firmly against them, and withstood their attack, telling them how insignificant a superiority of numbers is against true courage and bravery. The battle being thus divided, and fought in two different places, the Spartans were the first who broke in upon the Persian forces, and put them in disorder. Mardonius, their general, falling dead of a wound he had received in the engagement, all his army betook themselves to flight; and those Greeks, who were engaged against Aristides, did the same thing as soon as they understood the barbarians were defeated. The latter ran away to their former camp which they had quitted, where they were sheltered and fortified with an inclosure of wood. The manner, in which the Lacedæmonians treated the Platæans some time after, is, also, not unworthy of remembrance. About the end of the campaign, which is that wherein Mitylene was taken, the Platæans, being in absolute want of provisions, and unable to make the least defence, surrendered, upon condition that they should not be punished till they had been tried and judged in form of justice. Five commissioners came for that purpose from Lacedæmon; and these, without charging them for any crime, barely asked them, Whether they had done any service to the Lacedæmonians and the allies in war? The Platæans were much surprised as well as puzzled at this question, and were sensible that it had been suggested by the Thebans, their professed enemies, who had vowed their destruction. They therefore put the Lacedæmonians in mind of the services, they had done to Greece in general; both at the battle of Artemesium, and that of Platæa, and particularly in Lacedæmonia, at the time of the earthquake, which was followed by the revolt of their slaves. The only reason, they declared, of their having joined the Athenians afterwards, was to defend themselves from the hostilities of the Thebans, against whom they had implored the assistance of the Lacedæmonians to no purpose: that if that was imputed to them as a crime, which was only their misfortune, it ought not however entirely to obliterate the remembrance of their
- 29. former services. “Cast your eyes,” said they, “on the monuments of your ancestors, which you see here, to whom we annually pay all the honours, which can be rendered to the manes of the dead. You thought fit to entrust their bodies with us, as we were eye-witnesses of their bravery; and yet you will now give up their ashes to their murderers, in abandoning us to the Thebans, who fought against us at the battle of Platæa. Will you enslave a province where Greece recovered its liberty? Will you destroy the temples of those gods to whom you owe the victory? Will you abolish the memory of their founders, who contributed so greatly to your safety? On this occasion, we may venture to say, our interest is inseparable from your glory; and you cannot deliver up your ancient friends and benefactors to the unjust hatred of the Thebans, without eternal infamy to yourselves.” One would conclude, that these just remonstrances would have made some impression on the Lacedæmonians; but they were biassed more by the answer the Thebans made, and which was expressed in the most bitter and haughty terms against the Platæans, and, besides, they had brought their instructions from Lacedæmon. They stood, therefore, to their first question, “Whether the Platæans had done them any service during the war?” And making them pass one after another, as they severally answered “No,” each was immediately butchered, and not one escaped. About two hundred were killed in this manner; and twenty-five Athenians, who were among them, met the same unhappy fate. Their wives, who were taken prisoners, were made slaves. The Thebans afterwards peopled their city with exiles from Megara and Platæa; but, the year after, they demolished the latter entirely. It was in this manner the Lacedæmonians, in the hopes of reaping great advantages from the Thebans, sacrificed the Platæans to their animosity, ninety-three years after their first alliance with the Athenians. Herodotus relates, that cenotaphs, composed of heaps of earth, were raised near the town; but no vestige of these remain; nor are there any traces of the sepulchres of those who fell at Platæa. These
- 30. are mentioned by Plutarch, who says, that at the anniversary of those who were killed at Platæa, the Archon crossed the city to go to the sepulchres, and drawing water from the fountain in a vase, washed the columns of the tombs, and made libations of wine, oil, milk, and perfumes. Here was a temple of Minerva, in which Polygnotus executed a group of the return of Ulysses; and a statue of the goddess of great size, of gilt wood; but the face, hands, and feet, were of ivory. Also a temple of Diana, in which was a monument of Euchidas, a citizen of Platæa, to commemorate his having run from Platæa to Delphos, and returned before sunset: he expired a few minutes after. The distance was thirty-seven leagues and a half. Mr. Dodwell says, he could find no certain traces of this temple, nor of one dedicated to Ceres, unless several heaps of large stones might be regarded as such. Neither could he find any remains of a stadium. He saw, however, a frieze of white marble, enriched with Ionic ornaments. Dr. Clarke says, that the upper part of the promontory is covered with ruins; amidst which he found some pieces of serpentine porphyry; and the peasants, he says, in ploughing the soil in the neighbourhood, find their labours frequently obstructed by large blocks of stone, and earth, filled with broken remains of terra cottas. The ground-plot and foundations of temples are visible among the vestiges of the citadel, and remains of towers are conspicuous upon the walls. The walls form a triangle of about three thousand three hundred yards in compass. In some parts they are in a high state of preservation, and extremely interesting; since they were rebuilt in the reign of Alexander, after having been destroyed by the Persians. They are of regular masonry, eight feet in thickness, and fortified by towers, most of which are square.99 The view from the ruins is extremely interesting and beautiful. “When we look towards Thebes,” says Mr. Dodwell, “we behold the
- 31. Asopos, and the other small streams, winding through this memorable plain, which, towards the west, is separated by a low range of hills from the equally celebrated field of Leuctra; while the distant view is terminated by the two pointed summits of Helicon, and the snow-topped heights of Parnassus.”—“What must this city have been, in all its pride and glory!” exclaims Mr. Williams. “The remains now appear grey as twilight; but without a charm of returning day. Time is modelling now, instead of art. Miles of ancient pottery and tiles, hardly allowing the blades of corn to grow among the ruins; sheep-tracks among the massive foundations; asses loaded with brush-wood, from shrubs growing in the courts of ancient palaces and temples; shepherds with their flocks, the bells of the goats heard from among the rocks; tombs and sarcophagi of ancient heroes, covered with moss, some broken and some entire; fragments, and ornaments, and stones containing mutilated inscriptions;—these are the objects, which Platæa now presents. But who, that stands there, with a recollection of its ancient glory, and having Parnassus full in view, can quit the spot without regret?100”
- 33. Wreck of the mighty—relics of the dead— Who may remove the veil o’er Pæstum spread, Who pierce the clouds that rest upon your name, Or from oblivion’s eddies snatch your fame?— Yet as she stands within your mould’ring walls, Fancy—the days of former pride recalls; And at her bidding—lo! the Tyrrhene shore, Swarms with its countless multitude once more; And bright pavilions rise;—her magic art Peoples thy streets, and throngs thy busy mart. In quick succession her creative power Restores the splendour of Phœnicia’s hour, Revives the Sybarite’s unbless’d repose, Toss’d on the foldings of the Pæstum rose, Lucania’s thraldom—Rome’s imperial sway, The Vandal’s triumph—and the robber’s prey. But truth beholds thee now, a dreary waste; Where solitude usurps the realms of taste. Where once thy doubly blooming roses smiled, The nettle riots, and the thorn runs wild; Primeval silence broods upon thy plain, And ruin holds her desolate domain: Save where, in massive pride, three temples stand Colossal fragments of a mighty land. Sepulchral monuments of fame, that tower In proud derision of barbarian power; That still survive and mock, with front sublime, The spoiler’s vengeance, and the strifes of time. Rogers. When the president Dupaty first beheld Pæstum, he expressed his admiration in the following manner:—“No; I am not at Pæstum, in a city of the Sybarites! Never did the Sybarites choose for their habitation so horrible a desert; never did they build a city in the midst of weeds, on a parched soil, on a spot where the little water to be met with is stagnant and dirty. Lead me to one of those groves of roses, which still bloom in the poetry of Virgil.102 Show me some baths of alabaster; some palaces of marble; show me on all sides voluptuousness, and you will indeed make me believe I am at
- 34. Pæstum. It is true, nevertheless, that it was the Sybarites who built these three temples, in one of which I write this letter, seated on the ruins of a pediment, which has withstood the ravages of two thousand years. How strange! Sybarites and works that have endured two thousand years! How could Sybarites imagine and erect so prodigious a number of columns of such vile materials, of such uncouth workmanship, of so heavy a mass, and such a sameness of form? It is not the character of Grecian columns to crush the earth; they lightly mounted into the air; these, on the contrary, weigh ponderously on the earth; they fall. The Grecian columns had an elegant and slender shape, around which the eye continually glided; these have a wide and clumsy form, around which it is impossible for the eye to turn: our pencils and our graving-tools, which flatter every monument, have endeavoured in vain to beautify them. I am of the opinion of those, who think that these temples were the earliest essays of the Grecian architecture, and not its master-pieces. The Greeks, when they erected these pillars, were searching for the column. It must be admitted, however, that, notwithstanding their rusticity, these temples do possess beauties; they present at least simplicity, unity, and a whole, which constitute the first of beauties: the imagination may supply almost all the others, but it never can supply these. It is impossible to visit these places without emotion. I proceed across desert fields, along a frightful road, far from all human traces, at the foot of rugged mountains, on shores where there is nothing but the sea; and suddenly I behold a temple, then a second, then a third: I make my way through grass and weeds; I mount on the socle of a column, or on the ruins of a pediment: a cloud of ravens take their flight; cows low in the bottom of a sanctuary; the adder, basking between the column and the weeds, hisses and makes his escape; a young shepherd, however, carelessly leaning on an ancient cornice, stands serenading with his reedy pipe the vast silence of this desert.” Such was the language of Dupaty, when he entered these celebrated ruins; nor was his enthusiasm in any way misplaced.
- 35. Pæstum was a town of Lucania, called by the Greeks Posidonia and Neptunia, from its being situated in the bay. It was then called Sinus Pæstanus; now the Gulf of Salerno. Obscurity hangs not only over the origin, but over the general history of this city. The mere outlines have been sketched, perhaps, with accuracy; but the details are, doubtless, obliterated for ever. In scenery Pæstum yields not only to Baiæ, but to many other towns in the vicinity of Vesuvius; yet, in noble and well-preserved monuments of antiquity, it surpasses any city in Italy; the immortal capital alone excepted. The origin of the city may be safely referred to remote antiquity; but those are probably in the right, who would fix the period at which the existing temples were erected, as a little posterior to the building of the Parthenon at Athens. But even this calculation leaves them the venerable age of twenty-two centuries; and so firm and strong are they still, that, except in the case of extraordinary convulsions of nature, two thousand two hundred and many more years may pass over their mighty columns and architraves, and they remain, as they now are,—the object of the world’s admiration. Whatever age we may ascribe to the temples, certain it is that the city cannot be less than two thousand five hundred years old. It was founded by a colony of the Dorians, who called it Posetan; a Phœnician name for the God of the Sea, to whom it was dedicated. Those settlers were driven out by the Sybarites, who extended the name to Posidonia. The Sybarites were expelled by the Lucanians; and these, in turn, were expelled by the Romans, who took possession of it (A.C. 480). From this time the poets alone are found to speak of it. It was, nevertheless, the first city of Southern Italy, that embraced the Christian doctrine. In 840, the Saracens, having subdued Sicily, surprised the city, and took possession. The question now arises, to whom was Pæsium indebted for its temples? To this it has been answered, that, as the ruins seem to exhibit the oldest
- 36. specimens of Greek architecture now in existence, the probability is, that they were erected by the Dorians. “In beholding them,” says Mr. Eustace, “and contemplating their solidity, bordering upon heaviness, we are tempted to consider them as an intermediate link between the Egyptian and Grecian monuments; and the first attempt to pass from the immense masses of the former, to the graceful proportions of the latter.” “On entering the walls,” says Mr. Forsyth, “I felt the religion of the place. I stood as on sacred ground. I stood amazed at the long obscurity of its mighty ruins. They can be descried with a glass from Salerno; the high road of Calabria commands a distant view; the city of Capaccio looks down upon them, and a few wretches have always lived on the spot; yet they remain unnoticed by the best Neapolitan antiquaries.” The first temple103 that presents itself, to the traveller from Naples, is the smallest. It consists of six pillars at each end, and thirteen on each side. The cella occupied more than one-third of the length, and had a portico of two rows of columns, the shafts and capitals of which, now overgrown with grass and weeds, encumber the pavement, and almost fill the area of the temple:— ———The serpent sleeps, and the she-wolf Suckles her young. The columns of this temple are thick in proportion to their elevation, and much closer to each other than they are generally found to be in Greek temples; “and this,” says Mr. Forsyth, “crowds them advantageously on the eye, enlarges our idea of the space, and gives a grand and heroic air to a monument of very moderate dimensions.” In the open space104 between the first and second temples, were two other large buildings, built of the same sort of stone, and nearly of the same size. Their substructions still remain, encumbered with fragments of the columns of the entablatures; and so overgrown
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