On Agricultural Chemistrij. 



Table I.* 



Harvest 1844. Summary. (See first section of diagram I., 

 opposite p. 14.) 



Description of the Manures. 



Plot 3. Unmanured . . . . . 

 , , 2. 14 tons of farm-yard manure 

 , , 4. The ashes of 14 tons of farm-yard manure. 

 , , 8. Minimum produce of 9 plots with artificial 

 mineral manures : — 



Superphosphate lime 350 lbs. 

 Phosphate of potass 364 lbs. 

 , 5 15. Maximum produce of 9 plots with artificial 

 mineral manures : — 



Superphosphate lime 350 lbs. 

 Phosphate magnesia 168 lbs. 

 Phosphate potass 150 lbs. 

 Silicate potass 112 lbs. 



Mean of the 9 plots with artificial mineral manures 

 Mean of 3 plots with mineral manures and 65 lbs, 



eacli of sulphate ammonia 

 Mean of 2 plots with mineral manures and 150 lbs. 



and 300 lbs. of rape-cake respectively 

 Plot 18. With complex mineral manure, 65 lbs 

 of sulphate of ammonia, and 150 lbs. of rape- 

 cake ....... 



Dressed Corn 

 per Acre, 

 in Bushels 

 and Pecks. 



Total 

 Corn 

 per Acre, 

 in lbs. 



Straw 

 per Acre,, 

 in lbs. 



bush, pecks. 

 16 0 

 22 0 

 16 0 



lbs. 



923 

 1276 



888 



lbs. 



1120 

 1476 

 1104 



16 1 



9S0 



1160 



17 31 



1095 



1240 



16 3|- 



1009 



1155 



21 0 



1275 



1423 



18 If 



1078 



1201 



22 31 



1368 



1768 



The indications of the table are seen to be most conclusive, as 

 showing what was the character of the exhaustion which had been 

 induced by the previous heavy cropping, and what, therefore, 

 should be the peculiar nature of the supply in a rational system 

 of manuring. If the exhaustion had been connected with a defi- 

 ciency of mineral constituents, we might reasonably have expected 

 that by some one at least of the nine mineral conditions — sup- 

 plying in some cases an abundance of every mineral constituent 

 which the plant could require — this deficiency would have been 

 made up ; but it was not so. 



* It should be stated that the terms Superphosphate of Lime, Phosphate of Potass, 

 Phosphate of Soda, and Phosphate of Magnesia, as used in this and the foUowint; 

 Tables, and by which it is convenient to designate the manures, are not to be 

 understood as representing the chemical substances bearing those names. They were 

 formed by acting upon burnt bone-dust by means of sulphuric acid iu the first 

 instance, and in the cases of the alkaline salts and the magnesian one by neutralizing 

 the compound thus obtained by means of cheap preparations of the respective bases. 

 The Silicate of Potass was manufactured at a glass-house by fusing equal parts of 

 pearlash and sand — a transparent glass, slightly deliquescent in the air, was the result. 

 It was ground to powder under edge-stones. The Sulphate and the Muriate of Am- 

 monia were such as are usually sold for the purposes of manure, and it may be esti- 

 mated that one hundredweight of them respectively is equal to 100 lbs. of the pure 

 crystallized salt. The sulphuric acid used was of the specific gravity of about 1*7. 



