115 



" they be equally prepared to hear that oilj and tallow, and 

 " soap, are to be fabricated from the hardened mud of the 

 " coal mines — for such is shale." 



In Cornwall, also, I believe, the mining refuse is exciting 

 attention, and I understand that a weak description of sul- 

 phuric acid is obtained from it by distillation, which again is 

 used in the process of manufacturing common soda. 



It has frequently occurred to me as an extremely interest- 

 ing speculation, whether, as Chemical science advances, a 

 method may not be discovered of cheaply producing ammonia 

 from its constituents, hydrogen and nitrogen, obtained from 

 water and air, — the chemical combination being accom- 

 plished by the agency of Galvanism, or some other powerful 

 means. 



Having now given you the result of experiments very 

 interesting to myself, and which I hope will lead others to a 

 continued investigation of a subject that may ultimately be 

 productive of great advantage, allow me to call the attention 

 of those interested in Agricultural Chemistry to an analytical 

 table of the constituents of various cultivated plants, origi- 

 nally drawn up by those eminent chemists, Boussingault and 

 Sprengel, and which I have caused to be re-printed, with some 

 modifications and additions, from one furnished to me by Mr. 

 Haywood, analytic chemist, of Worksop. This table clearly 

 points out to the farmer the fixed constituents of any given 

 vegetable produce ; and the plain inference is, that unless his 

 crop can obtain those constituents from the soil, he must not 

 expect a perfectly developed plant, or, in other words, he 

 must look in vain for a good crop. If his land is deficient in 

 any of those constituents, they must be introduced artificially. 

 Under this system, I think it not too much to expect that, 

 with proper scientific management, even successive good 

 crops of wheat may be raised on the same land, by supplying 



