SOURCES Of Tllli PHOSPHATES* 345 



X SOURCES OF THE PHOSPHATES WHICH ARE FOUND IN THE CORN AND 



GRAZING SOILS OF NEW-YORK. 



It has been supposed that tlic phospliatcs were deiivctl I'loiu tlie coiiiniimiieil piiiaaiy 

 rocks contained in soils. Professor Fownes, author of a well known prize essay, has given, 

 in an appendix to his work, several analyses which he had made for the purpose of settling 

 the point whetiier the phosphates were contained in the ordinary g'ranites. His results 

 confirmed his suspicions, namely, that the phosphates were aenerally appreciate in the 

 granites, when a thousand grains were operated npon. In the New-England soils, the 

 disintegrated gneiss, mica slate, and granite which composes in the main those soils, con- 

 tain the phosphates of the alkalies and alkaline earths. In two of the districts which we 

 have closely examined, the phosphates are quite abundantly locked up in thc^ rocks, and 

 maj' be obtained when the analysis is conducted with ordinary care. Suspecting that the 

 taconic slates might contain these important elements, several analyses were undiutaken for 

 the purpose of ascertaining the truth of my conjectures. It was not, however, the principal 

 object to test the question merely for the local fact, but for tlie purpose of ascertaining a 

 more general result, one which should have an important bearing upon a widely extended 

 formation. I therefore selected a specimen of the taconic slate from Waterville, JMaine, 

 and several from Washington county, New- York. Prof. Jackson, in his survey of Maine, 

 had found phosphates of magnesia in those soils ; and as the slates of Waterville are 

 identical with the New-York slates which Ijelong to the same system, it appeared highly 

 probable that this formation would l)e found to contain the phosphates wliicii had been 

 detected so frequentl}- in the soils which rest upon those slates. I give the following 

 results, as the analj-ses show other elements of importance besides the phosphates. No. 1 

 is the Hoosic roofing slate, which contains the beaiitifid fucoid that I have already referred 

 to, when treating of the Taconic system ; No. 2 is the Waterville slate. Me.; and No. 3 

 is tlie crystallized taconjc slate, near and just west of the village of Salem, Washington 

 county. 



ANALYSIS. 



No. 1. No. 2. No. 3. 



Water 3-79 3-42 2-62 



Silica 70-55 71-62 84-65 



Alumina and peroxide of iron 20-35 23-25 11-53 



Carbonate of lime 0-99 0-10 0-60 



Potash 3-52 1-52 0-00 



Carbonate of magnesia 0-40 0-05 0-60 



Soluble silica trace. trace. trace. 



Phosphates trace. 0-90 trace. 



The potash obtained was merely a trace ; and the phosphates did not appear, until the 

 solution had been standing twenty-four hours in No. 3. 

 [Agricultural Report.] 44 



V 



