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much smaller proportion sugar, a small quantity of oil, 

 albumenoids and ash. The exact proportion of these different 

 elements was exhibited in bottles, thus giving the audience 

 a clear idea of the relative parts. Now all these substances 

 are obtained from the soil or atmosphere, and it is impor- 

 tant to know where each came from. Starch, sugar and oil 

 are composed of carbon, hydrogen and oxygen, these three 

 elements combining in different proportions in each of the 

 substances named. 



The remaining solid from the corn — the albumenoids — 

 is also composed of carbon, hydrogen and oxygen, to which 

 is added fifteen per cent, of nitrogen. The oxygen and 

 hydrogen are drawn directly from the soil in the form of 

 water, but primarily the water is furnished by the atmos- 

 phere ; the carbon also comes from the atmosphere in the 

 form of carbolic acid gas ; the source of the nitrogen is not 

 known, but the speaker believed that, with few exceptions, 

 it comes from the air. This would leave the ash alone to 

 be supplied by the soil. 



Applying the analysis of the five pound stalk of corn to 

 twenty tons (the crop of an acre) gives about the following 

 component parts of the entire crop : 32,580 lbs. of water, 

 2,400 lbs. of sugar, 1,394 lbs. of starch, 895 lbs. of fibre, 

 237 lbs. of fat, 75G lbs. of albumenoids and 408 lbs of ash. 

 Now the ash alone is supplied by the soil, while all the 

 other parts come from the air, and the question arises, 

 " Must we put back on the soil all of the ash taken by this 

 crop ?" and the speaker replied in the negative. Of the 408 

 lbs. of ash in the crop, 150 lbs. are silica (of which there 

 is plenty in the soil), 17 lbs. of magnesium (which does not 

 require replenishing), 17 of soda (which is not necessary 

 to the plant), 44 lbs. of phosphoric acid, 120 lbs. of potash 

 and 120 lbs. of nitrogen, the last three (284 lbs.) being the 

 only essentials of the ash, or of the whole plant product, 

 that it is necessary to put back into the soil. 



Here then are the necessary bases of manures and fertil- 

 izers, viz : nitrogen, phosphoric acid and potash. 



