BULLETIN OF THE BUSSEY INSTITUTION. 131 
one sure way to elevate its character, and that is by irrigation, ap- 
plied to grass or to other crops suited to receive it. In the case of 
this particular experimental field, it would not be difficult to keep 
the soil moist by pumping water with a windmill, either from the low 
valley mentioned on page 80, ‘upon the one side, or from the brook 
upon the other ; and the same thing might be done for a multitude 
of similar fields throughout the entire country. Mr. Marsh, in his 
“Man and Nature” (New York, 1864), p. 367, has urged long ago 
that the natural conditions of Piedmont and Lombardy, where irri- 
gation is bestowed upon almost every crop, are in some respects very 
like those which obtain in New England. ‘The summers in Northern 
Italy, though longer, are very often not warmer than in New England ; 
and in ordinary years the summer rains are as frequent and as abun- 
dant in the former country as in the latter. .... The necessity of 
irrigation in the great alluvial plain of Northern Italy is partly ex- 
plained by the fact that the superficial stratum of fine earth and 
vegetable mould is very extensively underlaid by beds of pebbles and 
gravel, brought down by mountain torrents at a remote epoch. The 
water of the surface-soil drains rapidly down into these loose beds, 
and passes off by subterranean channels to some unknown point of 
discharge.” 
The fact already noticed on page 126, that somewhat heavier crops 
were obtained from Square EE 8, known to have received some farm- 
yard manure in 1872, and from the other squares, numbered 7, 8, 
and 9 of that section, which are supposed to have had farm or stable 
manure thrown upon them in 1871 or 1872, is probably due to the 
great diffusive or penetrative power of the nitrogenous constituents 
of dung. Unlike ammonia and potash, the soluble nitrogenized 
constituents of dung are not immediately “fixed” on coming into 
contact with the soil. On the contrary, when dissolved in water, 
they soak into the earth in all directions ; and although the diffusion 
is undoubtedly hindered somewhat by the mechanical attraction of 
the soil, i.e. by mere adhesion, there is reason to believe that the 
substances in question are not actually arrested, or even very firmly 
held, until they have been changed to the condition of ammonia, or 
to that of some one of the more or less inert nitrogenous constituents 
of humus. On this view, it is evident that a soil manured with dung, 
i.e. with dung liquor, must be thoroughly charged in all directions 
