[25] POND-CULTUEE. 491 



As will be vseen from the figure, the iudividual distances of the ])urts 

 of the ditch from their corresponding points along the line of the dike 

 will — presuming the i)art of the dike assigned to u squad to be a and 

 the i)art of the ditch assigned to a squad b — be as follows: 



Squad 1 on the ditch = 1 a -{- lb 



Squad 2 on the ditch = 1 a + :ib 



Squad 3 on the ditch = '2a-\- .3 b 



Squad 4 on the ditch = 2 a + 4 & 



Squad -5 on the ditch = .'> « + 5 b 



Squad 6 on the ditch = 3 a + G Z> 



Squad 7 ou the ditch = 4 a + 7 b 



Squad 8 on the ditch = 4 « + Sb 



Squad 9 ou the ditch = 5 a + 9 b 



Squad 10 on the ditch = 5 a + 10 & 



We have here another progression, and it will, therefore, not be neces- 

 sary, as has been done in this case for the sake of illustration, to ascer- 

 tain the length of each part, but it will be sufiQcient to ascertain that of 

 the first and of the last squad, no matter whether the number of squads 

 is a hundred or any other number. The formula for this has already 

 been given under 1. 



3. The same applies to the curved lines. For our present purpose I 

 deemed it proper to choose the straight lines, because they will make 

 the method of calculation more intelligible. 



For 2 and 3 the same formula will, therefore, have to be used as for 

 1, in order to find the necessary' number of shovelers, and what has been 

 said there with reference to an even or odd number of squads will like- 

 wise apply here. 



If the fish-int, E F G H, is to be dug at the same time, the first terms, 

 1, 2, 3, 4, rei)resenting the squads working the parts 2 — 2 of the dike, 

 would be dropped from the above progression, because they and the 

 corresponding part of the ditch would be worked by the squads as- 

 signed to th-e fish-pit, which would also dig the portion of the ditch be- 

 tween 3 and 4, as soon as they do not need it for their arrangement, 

 and the number of squads IS", which would have to be used for ascer- 

 taining the number of shovelers, would now be G instead of 10, and the 

 first term for calculating the progression would be the 5th term, i. e., 

 the distance assigned to the 5th squad. The i^lacing of the laborers for 

 the fish-pit is done parallel with the dike on line F H, which may be 

 divided among 4 squads working in the same manner as the rest of the 

 squads ; for every distance exceeding 3.6 meters an additional shoveler 

 should be employed. 



The fish-i)it is dug out in the same manner as a large ditch. The 

 formula for ascertaining the total number of laborers required for con- 

 structing a dike with the necessary ditches, will, on the basis of the 

 fonnula given above for finding the number of laborers, excluding, how- 



