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PHILOSOPHICAL SOCIETY OF WASHINGTON. 
under others, and it is not maintained that it has any scientific 
value. 
Mr. Gilbert says that he hopes “to show that Mr. Finley’s method 
involves a serious fallacy. This fallacy consists in the assumption 
that verifications of a rare event may be classed with verifications 
of the predictions of frequent events without any system of weight¬ 
ing.” It is not perceived that Mr. Gilbert has furnished any such 
system. The fallacy, perhaps, consists rather in the supposition 
that any valuable result can be obtained by averaging the percent¬ 
ages of verification of heterogeneous classes of predictions. Mr. 
Finley correctly computed his indiscriminate percentage of verifi¬ 
cation, and thereby furnished a striking and, perhaps, much-needed 
illustration of the worthlessness of such computations. The elimi¬ 
nation of hypothetical chance from such mixed percentages merely 
renders their worthlessness less apparent. 
This paper was briefly discussed by Messrs. Curtis, Farquhar 
Hill, Baker, and Woodward. 
Mr. H. Farquhar presented a solution and generalization of a 
problem, proposed in Science^^ requiring the division of a rectangle, 
by a single step-cut, into two parts which when put together will 
form a square. 
Mr. Marcus Baker presented a communication on 
. A COLLECTION OF SOLUTIONS OP THE TRISECTION PROBLEM. 
[Abstract.] 
The communication consisted of an informal statement from notes 
and memoranda of progress in the direction of an exhaustive col¬ 
lection of real solutions of the problem to trisect an angle. It was 
pointed out that, though the problem was a very old and very 
famous one, energy is constantly wasted in its study by those igno¬ 
rant of what has been done, and that this misdirected energy might, 
in large part, be due to the want of any satisfactory digest of results 
hitherto attained. The author had himself felt the need of such a 
digest, and, finding none, had some years ago begun a collection of 
* See Ncie?ice. 4°. New York, 1887, May 20; vol. 9, no. 224, p. 488, 
query 5, 
