164 



FARMERS' INSTITUTES. 



"W. & L. E. Gnrley, of Troy, N.Y., sell an excellent instrument, as shown 

 l)elow. You can determine the amount of the grade quite accurately with a 



common carpenter's level as follows: 



Drive in two stakes, one each side of your ditch, and near the outlet; nail 

 or fasten securely in a horizontal position a cross piece from stake to stake, 

 and seven feet above the bottom of your ditch. You now have something 

 to work from, and by means of a simple carpenter's level you can now lay 

 out your ditch pretty accurately. Sights, each one-half inch above the level. 



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adds much to its accuracy, as in sighting over a plain surface the eye has to 

 be held somewhat too high, and there is a tendency to look somewhat too 

 low. With the eye alone, an error of one inch in six rods cannot be detected ; 

 hence the method to be described is unsafe on a level or nearly level grounds. 

 I think drains in peat ought never to be on a less grade than 1 in 300, which 

 is about two-thirds of an inch per rod. 



Start at the cross-piece near the outlet, rest a carpenter's level on it, sight 

 up the drain. If the level is three feet high in its first position and it strikes 

 the ground at any point, that ground would be three feet higher than the 

 ground near the level ; if it come within one foot of the ground, that ground 

 would be two feet higher ; if within four feet, the ground would be one foot 

 lower. In this way an approximate knowledge of the slope of the ground 

 can be obtained. 



