Corrections 203 
The Westminster Review.—Several of the early numbers ef 
this new work have been received from Mr. Maclure. 
Dr. Van Rensselaer’s Geology.—A copy of this work has 
been presented by the author. 
3. Correction communicated by A. B. Quinbys 
Pror. SILLimAn, 
Siz, 
Since my solution of the crank problem was pub- 
lished in your Journal, it has been stated to me by several in- 
dividuals, that ‘‘the London Journal of Arts and Sciences 
contains a solution of this problem, in which the writer finds the 
same result as that which! have established in my demonstra- 
tion.””? As this statement has recently been much reiterated, 
and as I wish not to rest under the charge of having copied 
the demonstration of another writer, I beg the liberty to state, 
publicly, in your Journal, that the solution published in the 
London Journal is not the same as that which I have given 
in, your Journal. The solution contained in the Loadon 
Journal, (Vol. 3. p. 252.) besides being different from mine, 
is erroneous ; and does not embrace the principles of the 
crank problem. The author makes precisely the same error 
as waS committed by Mr. Ward in your Journal; by as- 
suming that “ the effects produced at the several points of di- 
vision of the quadrant, are as the perpendiculars respectively 
from those points to the line of force.” This error is showa 
in my demonstration at page 318, line 2; and page 321, line 
8, Vol. VII. 
New-York, Aug. 24, 1825. 
A. B. QUINBY. 
N.B. There is a second paper inthe London Journalion 
the crank ; but it is less scientific than the first, and embraces 
the same error. 
A. B. Q. 
4. Correction communicated by G. W. Carpenter —In the 
communication on Cinchona Bark, p. 365, Vol. 1X, the fol- 
lowing passage, i. e. “ Experiments which I made upon the 
Carthagena bark, of rather better quality than the market 
generally produces, yielded about one twelfth less quinine 
