226 BOARD OF AGRICULTURE. 



reply, I would say, we do believe, absolutely, that chemical 

 science is more exact and trustworthy than almost any other ; 

 and we have no fear that any practical trial will invalidate the 

 statements of an intelligent chemist. This idea of restoring 

 the fertility of exhausted lands by the direct application of 

 chemical substances, which has been so ably presented in the 

 lecture this morning, is of immense importance. The experi- 

 ments of Dr. Nichols demonstrate the fact that potash and 

 phosphate of lime are the two most indispensable fertilizers. 

 These, therefere, we must constantly strive to procure as cheaply 

 as possible. Wood ashes and bones supply them in the most 

 desirable form, but they cannot be obtained in sufficient quantity. 

 We must therefore seek these precious substances in the rocks, 

 where they exist in exhaustless abundance. 



From saline deposits like those at Stassfiirth in Prussia, we 

 may now procure potassa ; and doubtless at no distant day we 

 shall be able to disintegrate by chemical or mechanical means 

 feldspathic and other minerals, and extract economicsflly their 

 contents of this valuable alkali. 



In regard to phosphate of lime, it is certain that enough may 

 be procured from the recently discovered deposits in South 

 Carolina to enrich all our worn-out lands, and preserve their 

 fertihty for thousands of years. Before, however, we can derive 

 the greatest possible advantage from this mineral phosphate we 

 must discover some method or rendering it soluble without the 

 use of sulphuric acid. This is now employed for converting the 

 mineral into superphosphate, but the process is very expensive 

 in consequence of the large amount of carbonate of lime asso- 

 ciated with the phosphate. 



Efforts are now making in the laboratory of the Massachu- 

 setts Agricultural College to accomplish this desirable result, 

 and, as we believe, with a reasonal)le prospect of success. 



The value of scientific knowledge to the farmer was never 

 more clearly demonstrated than in the discussion we have just 

 had respecting the preparation and use of special fertilizers. 

 When we have more educated agriculturists we shall save 

 much which now goes to waste, and many frauds, now common, 

 will be no longer possible. 



The greatest saving, perhaps, when knowledge abounds, will 

 be in words, for ignorance is the principal cause of the inter- 



