Mr. G. Calver.
From Walter Goodacre, Esq.
Seven Sisters Road,
May, 1879.
Dear Sir,—Respecting the 5-1/4 in., I am very much pleased with it; the definition is very good.
As a proof of the excellence of the mirror, I may mention that I have on several occasions seen the small crater on the floor of Helicon, given by Webb as a test for a 9 in. mirror.
Yours truly,
(Signed.)