178 Running Lines for Ditches. 
of the land to be irrigated), and running up stream a line which 
has the inclination intended for the ditch. 
To stake out this line when no special hindrances are in the 
way, use a home-made leveling instrument constructed as fol- 
lows :— 
With sound, straight-edged lumber a triangle is made, as indicated in 
the sketch. The three pieces, 4 2, 6feetlong, B C, 12 feet long, and C A, 
4 feet long, are made fast to each other at 4, &, and C. The board, A D, 
is fastened to the triangle at right angles to B C. Near A, on the board, 
A D,a plumb-line is made fast. The plumb, like a mason’s plumb, hangs 
in a hole at F, so that when A D is vertical, the string hangs very near the 
surface of the board, 4 D. 
FAO \, 
lh \ 
cae Pe re iN 
A Home-made Leveling Instrument. 
eC 
It will be seen that when 4 D is exactly vertical, B C is exactly hori- 
zontal, if the angles at D are true right angles. An ordinary carpenter’s 
square used in the construction of the apparatus will insure sufficient accu- 
racy in the position of 4 D. 
In marking on the board, A D, however, the line in which the string 
of the plumb will hang when BZ C is exactly horizontal, more care is 
required. Two pegs are driven, as far apart as B and C, for these points 
to reston. The highest one is driven into the ground until the plumb-line 
follows about the center line of the board, 4 D.- Having marked this 
position of the plumb-line, the triangle is reversed so that the end 2 rests 
on the peg where before we had the end CG, and vice versa. Should the 
plumb-line be ina position at variance with the first one marked on the 
board, then the correct position for the # C horizontal will be exactly in 
the middle between the two found by the aid of the two pegs. 
It will frequently be found convenient to have a scale of feet marked 
offon BC. Holes in the pieces 4 B and C A at Z E, or handles, will 
make the triangle convenient to carry. Only two men are necessary in 
using it. 
To use this instrument for locating the line of the ditch, 
calculate the amount which your line should rise between each 
two pegs. Drive a peg at the starting-point with its top say six 
inches from the general surface of the ground. Hold one end 
