FARMER'S ASSISTANT. 159, 



In this case, however, the leading drains should be no 

 deeper than the small ones, in order that the latter may 

 regularly be carried into the former; and, for this purpose, 

 spaces sufficiently large are to be left in the sides of these, 

 for the discharge of the waters of the small drains into the 

 leaders. 



If flat stones are to be used, the construction may be 

 similar to the foregoing; or, after the bottom has been laid, 

 the side-stones may be set up, say, ten inches apart at the 

 bottom, and leaning against each other at the top, so that 

 the aperture thus formed by them will be of a triangular 

 shape. Billets of wood, of any durable kind, may also, in 

 like manner, be used for forming the. aperture, as such 3 

 when buried so deeply beneath the surface, will probably 

 last from fifty to one hundred years. 



Where the descent of the leaders is very gentle, there is 

 no necessity of a layer of brick or stone to form the bottom, 

 as in such case the current of the water would not wear 

 any of the earth away ; but, where the descent is more 

 rapid, it is necessary to secure the bottom from being 

 washed by the runing of the water ; otherwise the drains 

 would soon become stoped : And, where the bottom is thus 

 secured from wearing, the descent of the drains may be 

 considerably rapid, without any danger of being injured by 

 the waters which pass through them. 



There are several methods of making the small drains, 

 some of which are more expensive than others. The more 

 expensive methods will be found the most durable; and yet 

 not always, on that account, the most advisable. Suppose, 

 for instance, that by one method of construction the drains 

 would last forever; that this method should cost fifty dollars 

 an acre; that, by another method, which should cost forty 

 dollars an acre, they could be made to last sixty years; 

 which, in that case, would be most advisable ? 



Undoubtedly the latter. Two dollars and fifty cents put 

 at interest, at seven per cent; and doubling, as it will, at 

 the end of about every fourteen years, give upwards of forty 

 dollars at the end of sixty years; of course there would be 

 a saving of about seven dollars and a half of capital, by 

 making the drains on this cheaper construction. 



The most costly construction of the small drains would 

 be such as we have before described for the leaders; but 

 on a smaller scale. The cheaper constructions are, to dig 

 them very narrow at the bottom, and then lay in some sub- 

 stances through which the waters can readily find their 

 way into the leaders. For this purpose, very coarse gravel, 

 \vhich contains little or no mixture of line earthy matter, 

 has been successfully used, and this generally forms a very 

 durable drain. 



