There are two methods of estimating the value of excavating. It may be done by allowing so much a day for every man's work, or so much per cubic foot, or yard, for all that is excavated.

Well Digging. - Suppose a Well is 40 feet deep, and 5 feet in diameter, required the number of cubic feet, or yards?

5 X 5 = 25 x .7854 = 19.635 X 40 = 785.4 cubic feet. Suppose a well .o be 4 feet 9 inches diameter, and 16i feet from the bottom to the surface of the water; how many gallons are therein contained? 4.752 X 16.5 X 5.875 = 2187.152 gallons. Again, suppose the well's diameter the same, and its entire depth 35 feet; required the quantity in cubic yards of material excavated in its formation.

4.752 X 35 X .02909 = 22.9?2 cubic yards. A cylindrical piece of lead is required 7½ inches diameter, and 168 lbs. in weight; what must be its length in inches ?

7.52 x .3223 = 18, and 168÷ 8 = 9.3 inches.

Digging for Foundations, etc.- To find the cubical quantity in a trench, or an excavated area, the length, width, and depth must be multiplied together. These are usually given in feet, and therefore, to reduce the amount into cubic yards it must be divided by 27.

Suppose a trench is 40 feet long, 3 feet wide, and 3 feet deep, required the number of cubic feet, or yards?

40 x3 = 120x3=360feet ÷ 27 = 13 1/3 yards. 24 cubic feet of sand, 17 ditto clay, 18 ditto earth, equal one ton. 1 cubic yard of earth or gravel, before digging, will occupy about 1½ cubic yards when dug.