NITHATE OF SODA. 81 



or modes of using- nitre to the soil, it is not uncommon to find il 

 associated with soot, or with vegetable mould, substances which 

 require no assistance of any kind to constitute them powerful 

 manures, and the addition of which is therefore calculated to raise 

 strong doubts of the advantageous qualities ascribed to nitre alone. 

 Were the advantages of nitrate of potash much less questioned 

 than they are, however, the high price of the salt would probably 

 always oppose insuperable obstacles to its employment. This is 

 the reason, in all likelihood that has turned the attention of Eng- 

 lish agriculturists, for several years past, to nitrate of soda, a salt 

 that is imported in quantity from Peru, and of which the price 

 per cwt. may be about forty shillings ; a price which, were it found 

 really useful, would permit of its being used. Admitting the ac- 

 curacy of the experiments that have been made, indeed, we can- 

 not doubt the efficacy of nitrate of soda on soil already furnished 

 with organic manure. The quantity that has been recommended 

 is about one cwt. per acre. 



Mr. Barclay made a few experiments after having heard muph of 

 the nitrate of soda from his neighbors, of the results of which the 

 following examples will suffice to give a comparative estimate : 



Without nitrate. With nitrate. Difference in favor of 



the nitrates. 



Wheat 31 bush. 2 pecks. 35 bush. 3 pecks. 5 bush. 3 pecks. 



Straw 21 cwt. qrs. 19 lbs. 23 cwt. 2 qrs. 26 lbs. 3 cwt. 2 qrs. 7 lbs. 



The produce of the land treated with nitrate, however, did not 

 fetch so high a price at market as that grown without it ; and every 

 item of expense taken into the reckoning, the use of the nitrate was 

 attended with no commercial benefit. Still this does not militate 

 against the fact, that the production of vegetable matter was in- 

 creased upon land treated with the nitrate of soda. And indeed 

 much of the information which M. de Gourcy collected in England, 

 is of a kind that tends to confirm the favorable influence of this salt 

 on vegetation. Wheat, clover, and Swedish turnips are particular- 

 ly specified as benefiting from its use. These facts admitted, we 

 rnay ask : how does the nitrate of soda act ? The chemical consti- 

 tution of the nitrates is such, that we might conceive their acting at 

 once as mineral and as organic manures. The important point for 

 solution was to ascertain whether the azote of the nitrate contribu- 

 ted in any way to the formation of the azotized principles of plants. 

 Davy, in taking with much distrust the report of Sir Kenelm Digby's 

 experiments on the influence of nitre in the cultivation of barley, 

 shows no disinclination to believe that the azote of the salt may 

 concur in the production of albumen and gluten.* This, however, 

 is a point in physiology which may be put to the proof by experi- 

 ment, and seems peculiarly worthy of being tested in this way. I 

 have admitted it as extremely probable, that the azote of the azoti- 

 zed principles of plants has its source either in the ammonia, which 

 18 the special iltimate product of the organic manure we employ, ox 



- -. Agricultural Chemistry 



•27* 



