This document provides information on various types of engineering scales and their construction and applications. It discusses plain scales, which can measure dimensions up to a single decimal place, and provides examples of their construction and use. It also covers diagonal scales, which can measure up to two decimal places, and vernier scales, which also measure up to two decimal places. Comparative scales are described for comparing different units, and scales of cords are introduced for measuring and constructing angles. Construction techniques and example problems are provided for different scale types. The document serves as a reference for understanding and applying various engineering scales.