870 



THE COMPLETE GRAZIER. 



best tiles where the subsoil is a running sand. A mode of filling up 

 drains, that has found considerable favour, is the "tube" drain, 

 fig. 376; a b the trench, c the tube (which, in the diagram, should 

 lie at the bottom of the drain), d the filling up of soil, &c. In most 

 cases the tubes are placed in the trench simply end to end; in 

 other cases the end of each drain-pipe fits into the expanded end 

 (socket) of the succeeding one. 



It seems to be generally admitted that the 1-inch bore pipe-tiles are 

 not to be depended upon for drains, being very apt to become clogged, 

 and not to afford a sufficient channel for the water. Plain cylindrical 

 pipe-tiles are, however, the best that can be employed. For strong 

 lands, and where the drains are frequent, a bore of 2 inches in diameter 



Fig. 374. Fig. 375. Fig. 376. 



Different Methods of Filling up Drains. 



will be found sufficient, and the size of the pipe may be increased as it 

 approaches the outfall. For deeper drains in friable subsoils a bore of 

 nearly twice that size will be requisite. The pipes for the main drains 

 must always be capable of carrying off the water from all the pipes 

 which discharge into them. 



The following remarks on various points of detail in laying down 

 drains, from an able Essay in the " Transactions of the Highland and 

 Agricultural Society of Scotland," will be useful here : 



" In laying out the main drains and outlets, therefore, care must be 

 taken to calculate with as great certainty as possible the quantity of 

 water likely to be discharged. To determine the capacity in square 

 inches of any circular pipe, square the diameter, and multiply by 

 0*7854. For example, a pipe having the diameter of 12 inches will, 

 when square, equal 144, and this, multiplied by 0*7854, will give 

 113*097,6, or a little more than 113 square inches. The discharging 

 power, however, of these large circular pipes is much greater than a 

 square or horse-shoe tile drain of equal sectional area. There is little 



