174 RESULTS OF EXPERIMENTS WITH NITRATES. 



These 20 grains contain only 3 grains of nitrogen. Can this 

 minute quantity, supposing it all to enter the plant, really be 

 the sole cause of the observed results ? 



3. Results of past experiments with the nitrates ofpotash^ 

 soda, and lime. 



It is almost unnecessary to insert the results of the numerous 

 experiments which have been made of late years, especially with 

 nitrate of soda. A great number of the published experiments 

 with the latter nitrate have been inserted in my Lectures* I 

 shall, therefore, here make a selection, chiefly from results which 

 have not been introduced into any of my previous works. 



1. Experiments upon wheat. 



a By Mr John M'Clelland, near Wigton, 1843 : 



Grain. Straw. Weight of bushel. 



Nothing gave 1748 Ib. 2824 Ib. 63^ Ib. 



Saltpetre, 1| cwt., 1919 ... 3652 ... 63^ ... 



Increase, 1 71 ... 828 ... 



I By Mr John Haxton, near Cupar-Fife, 1843 : 



Grain. Straw. Weight of bushel. 



Nothing gave 1549 Ib. 3540 Ib. 60^ Ib. 



Saltpetre, 80 Ib., 1968 ... 4472 ... 63f ... 



Increase per imp. acre, 419 ... 932 ... 3^ ... 



c By Mr John M'Lintock, near Glasgow, 1843 : 



Grain. Straw. Weight of bushel. 



Nothing, 2689 Ib. 3372 Ib. 60j Ib. 



Saltpetre, 84 Ib., 2664 ... 3136 ... 60^ ... 



Diminution per acre, 25 ... 236 ... t 



Grain. Straw. 



d Nothing, 40 bush. 27 cwt. 



Nitrate of soda, 3cwt. 50 ... 39 J ... 



Increase, 10 ... 12 J ...J 



* Lectures on Agricultural Chemistry and Geology, 2d Edition, p. 593, et scq. 

 t Transactions of the Highland Society, January 1849, p. 437. 

 t Ibid. March 1849, p. 531. 



