The markings on Mars were well defined. I find the advantage of a large aperture shows itself. I have no doubt I picked up the outer Satellite, but cannot be certain till to-night, if I am permitted to see it. The only objection I have is its short focus, as it seriously complicates my labours in matching the secondary convexes for the Cassegrain form—if you can help me in the matter of a longer focus; if not I am satisfied and thankful, and must only proceed to the testing process inch by inch.
Yours truly,
(Signed.)
Mr. G. Calver.
From the same Gentleman.
Carlisle Terrace, Malahide,
November 6th, 1877.
My Dear Sir,—I had intended to write to you before, but, from various duties, I have been obliged to postpone it from day to day. I have been working steadily, however, with your 18″, and I like it the more I use it. The figure is wonderfully perfect, and the definition of planetary details and markings most admirable.