SILVERING AND POLISHING SPECULA.

£ s. d.

5 inch 0 6 0

6-1/2 〃 0 8 0

8-1/2 〃 0 10 6

10 〃 0 15 0

12-1/2 〃 1 1 0

Diagonal Planes 3s. to 0 5 0

New Edition of Hints on Silver-Glass Reflecting Telescopes Manufactured by Mr. G. Calver, F.R.A.S. with Directions for Silvering, Adjusting, &c. · 第 32 / 62 题