Irrigation. 89 



the surface, otherwise in the same fashion as by surface irrigation. 

 Reports of wonderful crops produced on slopes of soil by 

 no means rich, under a new system called by the inventor (A. N. 

 Cole) " aquaculture " (water culture), or new agriculture, have 

 recently attracted considerable attention ; but since this method 

 is quite expensive, and possible only under certain conditions, 

 namely, on a slope with impervious clay subsoil, it is not of 

 general utility, nor excessively meritorious. Mr. Cole gives the 

 following description of it : " A ditch is opened on a water level 

 along the hillside or slope, say a yard wide, and from three to 

 five feet deep. At the bottom of this ditch are loosely placed 

 cobble and blocky stones, for a loot or two, then flat stones are 

 laid over these, then a quantity of smaller stones ; these are 

 covered over with weeds, briars, brambles, fine brush, straw, 

 corn stalks or other available material, to prevent the fine earth 

 from falling among and filling the crevices between the stones. 

 A heavy coating ot manure may follow, and then the excavated 

 soil is spread over it, and a terrace is graded if desired. What- 

 ever course the trench may take, the surface of the hard pan at 

 the bottom of the ditch must never vary from a water level. A 

 series of such ditches, one above the other, are dug a rod or so 

 apart and similarly filled, over as large a surface as is to be 

 improved, each forming an elongated reservoir which will be filled 

 by the water-courses cut off, or by the melting snows and early 

 rains ; and if the subsoil is firm clay, or hard pan, it will be 

 retained, and as the surface soil dries, absorbed by capillary 

 action, and brought within reach of the roots of vegetation. 



" The connecting overflow trenches should be in the subsoil, 

 and filled with fine stone to the depth of a foot at least, and 

 shingled with flat stones in the same manner as the reservoir 

 trenches. This shingling should be of sufficient depth to escape 

 the plough or the deepest spading. The head of the overflow 

 trenches at the base of the slope should be at least twelve or 

 eighteen inches above the bottom of the reservoir." 



Cross-section of slope thus sub-irrigated is presented in 

 engraving. A is the surface soil ; B, the reservoir trenches ; C, 

 the sub-soil ; D, the connecting overflow trenches (which might 

 be laid with tile, where that can be had conveniently and cheaply), 

 and E, the outlet of drainage trench. I have given this for 

 information more than in the expectation that many readers will 

 make practical use of it. 



