228 GEOLOGICAL SURVEY 
Chlonne!.: 222. See ee eee OO ee TS 
amesre cle oe eee) ne ee ee ee ee Oi 
Mapnesian! 2252-22 e 42 eo OS meena Ih G's 
Potash: 4! Sa 3...c2 2 oe aelce ee cee ROM Ceepeet NO) 
Od geen le oe ee ea ee eee 2160) 
Silicase 2. s-2 = Sere eee Oho) ee SIS 
Alumina, SoC 222 oo ceriasjae ee oP Deo one end 
Moisture and loss=aoeep see ace oe ee ae eno 
40 lbs. 59 lbs. 
The other crops yielded, per acre, 
As stored. Dried. Ash. 
Clover hay. -----.------ 4,620 lbs.- .3,680 lbs. 283 lbs. 
Potatoes aoe ee cn el 4 60ers UIs sae 
Swedish turnips. -_.- .--~ 44,800-_ -.. --3,360- . _ -255 
The ashes gave the following weights of inorganic matters. 
Potato ash. Turnip ash. Clover ash. 
Phosphoric acid__--. - 16.05 Ibs... . 15.55 lbs.- -. 17.82 lbs. 
Sulphuric acid ---.--.- NOMS Seo 2 eae AOS 
Carbonic acid.__---_- NOFO See = soos Osama ar 70.85 
@hilorines 24. 222-2 ee is) ena ee (er ts Paes AY h319) 
hime Be ect ae Bode eee el Osan 090m 
Magnesiak soos set 23 (EY ese LO:962- sea 17.83 
Botash®. se 65 222 2 (onl oan ae OO ae eas Sis 75.18 
Sodazs sete cs oss traces cea LO AGS see ola 
Silica: = eee eceeee = O0-—  elbeee == 215,00 
INUMInaOCCeee ee sa ele ieee 00h en sce 0.85 
Moisture and loss... .99_.:.---14.02.2._ 22 —= 
142 lbs. 255 Ibs. 283 lbs. 
Knowing the weight of the crop taken from an acre, it will be easy to calculate, from these 
tables, the quantity of the inorganic elements that are removed each season. 
The difference between the weight of the ash of the grain, and that of the straw, is remarkable 
and interesting. The quantity of potash in the straw of the wheat and oats, is double that in the 
grain; while the total quantity of the straw-ash of wheat, is nearly five times as great as that in 
the grain. 
This points directly to the necessity of saving the straw and other refuse of the crop, for the 
purpose of returning them to the soil. 
When it is recollected that many of the most important of these ingredients exist in the soil, in 
very minute quantities, it should not excite surprise that a succession of crops, without any return 
to the soil, should, in time, so diminish them as to produce sterility. Could we await the formation 
of a new soil, by the further decomposition of the subjacent rocks, or of the mineral constituents of 
the sub-soil, and the accumulation of organic matter from the atmosphere, we could, in time, renew 
the same system of cultivation; but as this is impossible, we must have recourse to some means of 
restoring to the soil the matters that have been abstracted from it. 
This leads us to the subject of manures, on which a few observations will suffice. 
