494 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [28] 



many meters as 30 centimeters is contained in the difference between 

 the even and the uphill roads. In going downhill the same rule applies 

 as on an even road. The above, of course, only applies to horses ; if 

 oxen are employed only 0.7 of these figures should be counted. The 

 cubic contents, K, of the earth to be removed in one hour is : 



K = 



450. 7000 

 6w+ 4900 



cubic centimeters, 



Fig. 8. 



and in order to ascertain how many carts or wagons, W, are required 

 to remove the quantity of earth dug out by two men in one hour the 

 following formula will have to be used : 



(Gw + 4900) 

 ~ 7000 



We now have to speak of 



THE CONSTRUCTION OF THE EARTH-WORKS. 



In constructing large ditches, such as the main ditches and those for 

 letting the water in and out, it will be found a great aid in constructing 

 their walls or sides to dig out perpendicular steps 30, 60, and 90 centime- 

 ters high. These steps should vary 

 in breadth froui 15 to 00 centimeters; 

 their breadth, however, will greatly 

 depend on their height and on the 

 angle of the slope. Only those on 

 which laborers are to stand must at 

 least be 90 centimeters broad. The 

 Perpendicular sides a a of these 

 steps (see the figure) should be 

 distant about 15 centimeters from 

 the proposed walls of the ditch, so 

 that these may not be damaged. 

 The breadth of the first step, car- 

 ried inward from the terraced level 

 edge of one of the sides of the ditch, 

 supplies the end points for the line 

 h c, along which the laborers are to 

 be placed, and the same principle 

 applied to the other side of the ditch supplies the line g h, tlie limits of 

 the first prism a' a' a' a' to be dug out. In order to accelerate the work 

 it will be advisable to mark with pegs the piece assigned to each squad of 

 laborers. The laborers are placed, according to the direction (either right 

 or left) of the lines of work from the ditch towards the dike, in such a 

 manner as to place one squad on the line b c, and the next on the line 

 a h, JBefore the shovelers can be employed to move the earth farther, 



