SOURCES OF THE PHOSPHATES. 
345 
X SOURCES OF THE PHOSPHATES WHICH ARE FOUND IN THE CORN AND 
GRAZING SOILS OF NEW-YORK. 
It has been supposed that the phosphates were derived from the comminuted primary 
rocks contained in soils. Professor Fownes, author of a well known prize essay, lias given, 
in an appendix to his work, several analyses which he had made for the purpose of seUling 
the point whether the phosphates were contained in the ordinary granites. His results 
confirmed his suspicions, namely, that the phosphates were generally appreciable in the 
granites, when a thousand grains were operated upon. 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 cpiite abundantly locked up in the rocks, and 
may be obtained when the analysis is conducted with ordinary care. Suspecting that the 
taconic slates might contain these important elements, several analyses were undertaken 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 the 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, Maine, 
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 belong to the same system, it appeared highly 
probable that this formation would be found to contain the phosphates which had been 
detected so frequently in the soils which rest upon those slates. I give the following- 
results, as the analyses show other elements of importance besides the phosphates. No. 1 
is the Hoosic roofing slate, which contains the beautiful fucoid that I have already referred 
to, when treating of the Taconic system ; No. 2 is the Waterville slate, Me.; and No. 3 
is the crystallized taconic slate, near and just west of the village of Salem, Washington 
county. 
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. 
Phosphates_ _ 
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 
