478 



STATE BOARD OF AGRICULTURE. 



curatelv made as the more expensive instruments, but they are suffi- 

 ciently accurate for use where there is a fair fall, or grade, and for 

 other than professional engineers. Three such levels are shown in Fig. 

 10. 



With the level there should be a leveling rod. Fig. 11 shows two such 

 rods. One, A, is known as the sliding rod. It consists of two parts, 

 each in this case five and one-half feet long, fitted together and clamped 

 in such a way that they may be extended to form a rod ten feet long. 

 A rod like A is shown extended in B. The other rod, C, consists of 



Fig. 11. Two kinds of leveling rods. 



a single piece ^^'xl^'^xS ft. long. These rods are graduated to feet 

 1/10 ft. and 1/100 ft. Rods are sometimes graduated to feet, inches, and 

 fractions of an inch. • 



Sometimes the face of the rod is spaced or blocked in colors, the 

 spaces or blocks representing fractions of a foot, so that the graduated 

 face can be read at a distance and especially through the telescope of 

 the level. The face of rod (C) in Fig. 11 is so spaced. 



Each of the rods shown in Fig. 11 is equipped with a target. The 

 target is a circular plate divided into quarters by a horizontal and a per- 

 pendicular line, and the quarters painted red and white as shown. The 

 target is constructed to slide up and down in grooves on the rod or upon 



