LEACHED AND UNLEACHED ASHES. 217 



certain soil, they do not know by its chemical ingredients what 

 crop it is best fitted to produce ; that the air may furnish some 

 elements while the plant is growing. This was strikingly illus- 

 trated by the inquiry in regard to leached and unleachcd ashes. 

 There is a very general opinion, and I certainly have entertained 

 it, that leached ashes produced a good effect for a long series of 

 years. For fifteen, twenty, twenty-five years, their effects can 

 be seen on grass land. The doctor puts them at one-third the 

 value, chemically, of unleachcd ashes. I think there will be 

 difficulty in persuading the farmers of the Commonwealth that, 

 practically, there is this difference, although chemically he finds 

 it so. The question I wish to ask is, — and I ask it in order that 

 his statement may go out to the Commonwealth fortified with 

 all the assurance he can give, if he is of that opinion, — the 

 question I wish to ask him is, whether chemists feel satisfied, 

 beyond all question, that chemical results can be followed with 

 the faith with which he has asserted them here to-day ? I think 

 that such an assurance as that would add greatly, in the minds 

 of the public, to the good effect of the lecture, in satisfying 

 them that there is something by which we can supply the defects 

 in some soils. 



Dr. Nichols. I would say, in reply to this inquiry, that I 

 have great faith in the absorbent power of the soil. Of course, 

 the audience understand that we cannot obtain from the atmos- 

 phere anything which we get from the potash. I have always 

 been extremely cautious not to overestimate the value of 

 chemistry to agriculture. I have endeavored to be so to-day. 

 I think chemistry is capable of aiding us very materially ; but 

 when the question comes up whether the relative value of 

 leached and unleachcd ashes is what I have stated, I should say, 

 chemically, I am not certain. I suppose some soap-boilers do 

 not remove the same quantity of potash that others do. I can 

 see no necessary connection between the application of unleachcd 

 ashes to the soil and the atmosphere whatever. I am quite 

 aware that leached ashes contain soluble silicates to a certain 

 extent ; they are not exhausted of their entire fertilizing prin- 

 ciples ; but they are exhausted of those elements which we find 

 to be essential to plant growth. If leached ashes are just as 

 good as unleachcd ashes, I should advise you to buy all the un- 

 leachcd ashes you can, leach them, and sell the potash, for you 



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