54 



ENGINEERING FOR LAND DRAINAGE. 



-3- 



ease of computation, the decimal scale of feet and 

 tenths is best, though some prefer to use feet and 

 inches. 



Fig. 10 shows a form of rod which has been found 

 convenient and serviceable for drainage surveys, and 

 one which can be readily and cheaply 

 made. It is made of a strip of straight- 

 grained white pine, i inch thick, 2^ inches 

 wide, and lO feet long. The ends are 

 shod with J-inch iron to protect them 

 from battering. The rod is cut in two in 

 the middle and a good strap hinge set in 

 even with the face, so that the rod can be 

 folded together for convenience in trans- 

 portation. It is fastened open while in 

 use by a rib of wood, which is screwed fast 

 to the back, and covers the joint, and has 

 a movable bolt and thumb-nut for use in 

 holding the rod open or shut as desired. 

 The accompanying cut shows the manner 

 of graduating it. The dark spaces show- 

 ing tenths of a foot are red on the rod. 

 The foot figures are large and are painted 

 red. The tenth figures are black, and the 

 small squares along the centre line are also 

 black. There are two hundredth spaces, 

 ^j- and may be divided by the eye so that 

 reading Rod. the rod reads to single hundredths of a 

 foot. The variety and combination of colors are such 

 as to be clearly read at a distance of from three hun» 

 dred to five hundred feet, according to light and power 

 of the glass. 



Fig. ic- 



