63 



Calcium Sulphate. 

 Moisture at 100° C, 

 Calcium oxide, 

 Sulphuric acid, 

 Insoluble matter. 



Lime. 



Calcium oxide, 

 Insoluble matter, 



18.02 per cent. 

 32.40 " 



42.08 " 

 2.35 " 



88.64 per cent. 

 4.71 " 



For the purpose of comparison I include here figures showinor the 

 amounts of nitrogen, phosphoric acid and potash in the fertilizers 

 used, and in the below stated quantities of the crops which have been 

 under experiment. 



Contained in 



Nitrogen, 25 



Phosphoric acid, 49 

 Potash, 80 



It will be noticed that nitrogen is applied in considerably less 

 amount than is required by either corn or oats ; but in about double 

 the amount in the potatoes. Phosphoric acid and potash, on the 

 other hand, with one exception, (potash in the case of oats) are 

 applied in quantities considerably in excess of the amounts found in 

 good crops of the respective kinds under consideration. 



Yet our experiments indicate that potash does not particularly 

 benefit the oat crop, while it seems usually to be the most important 

 ingredient of fertilizer for corn and potatoes. 



The manures used in the several experiments varied widely ; but 

 with one exception (Shelburue) they supplied all the elements of 

 plant food in much larger quantity than the " complete" fertilizer. 

 The excess of nitrogen applied in the manure as compared with the 

 fertilizers is especially large. In the fertilizer we supplied at the 

 rate ot about twenty-five pounds of nitrogen ; in the manures, in differ- 

 ent experiments:— 111.9, 118.8, 69.4, 289.5, and 131.6 pounds per 

 acre. 



After ploughing, manures and fertilizers were in all cases spread 

 broadcast and harrowed in, just previous to planting the seed. 



Each experimenter was furnished with a standard maximum and 



