106 COTTOX CULTURE. 



As a cheap yet effective tool for laying off this grade, 

 the following is given. It is Mr. Forman's, with one or 

 two modifications. 



Select a piece of ash or oak, just ten feet long, one inch 

 thick, and four inches wide. Mortice it into a leg or sup- 

 port of pine, three feet long, and two inches square. 



Make another leg three feet and one inch long, and cut 

 the mortice several inches long, so that the bar or lath can 

 be moved up or down so as to vary the length of the fore 

 leg, as compared with the hind leg, two or three inches. 



This may be omitted entirely if cheapness is an object 

 and the bar fastened by screws, which can be drawn so as 

 to make any necessary variation. If put together so that 

 each leg shall be of the same length, the variation can 

 easily be made by screwing a block of an inch or more in 

 thickness on the foot of the front leg. 



To complete this instrument and fit it for use, it will be 

 necessary to fasten on it a small spirit-level ; this can be 

 screwed upon the side of the bar near one end, or on the 

 top of it. Probably a long slender phial, nearly filled 

 with some colored fluid and fastened to the top of the bar, 

 would give a sufficient degree of accuracy. Now having 

 determined upon the slope of the ditch, arrange the length 

 of the legs accordingly. Your assistant stands at the 

 point where you wish the water to be discharged, that is, 

 fit the bottom of the hill, and he has the hind leg. He 

 carries a handful of pins in his hand. The operator at the 

 front leg moves that end either up or down the slope, un- 

 til the bar is level. Mark the beginning point with a pin, 

 and move on, setting the hind leg in the track just made 

 by the fore leg, and sticking a pin. The path thus indi- 

 cated by the row of pins is the line of the hill-side ditch. 

 It should go three or four inches into the subsoil, and care 

 should be exercised so as not to have short turns, as their 

 effect is to throw the descending water against the em- 

 bankment. 



