13 
Ordinary Meeting, October 18th, 1864. 
J. P. Joule, LL.D., F.R.S., &c., Vice-President, in the 
Chair. 
Mr. Brothers, F.R.A.S., exhibited a photograph of the 
moon, which he had made from a negative by Warren De la 
Rue, F.R.S. The original negative is one inch in diameter, 
and from this a positive two inches in diameter was first 
made. This was placed within the rays of a nine-inch con- 
denser of the solar camera, and an enlarged negative on a 
plate 36in. by24in. was produced. The print exhibited was 
on a single sheet of paper, and thus the disadvantage of join- 
ing several sheets together as in other large prints of the 
moon was avoided. Various effects from the same negative 
could be produced by providing either for the finer details of 
the strongly illuminated side of the moon, or for the more 
rugged parts at the side near and at the termination of parts 
in shade. During the conversation which followed, Mr. 
Brothers stated that the negatives were the property of 
Messrs. Smith and Beck. It was suggested by Mr. Baxendell 
that more accurate micrometrical measurements could be 
made from such a photograph than direct from the moon’s 
surface in the telescope — in the one case the object being 
still, and in the other in constant motion ; and Dr. Roscoe 
remarked that if a series of the several phazes of the moon 
on the same scale as the one shown were published, he 
Proceedings — Lit. & Phil. Society — Yoi. IY.— No. 2 — Session, 1864-5. 
