One result of the application was a permanent injury to my sight.
"Wanting some object on which to apply my newly-acquired mathematical knowledge, I determined to construct an astronomical telescope.

I got Airy's 'Geometrical Optics,' and read it through.

Then I searched through all my English Mechanic (a scientific paper that I take), and prepared for my work by reading all the literature on the subject that I could obtain.

I bought two discs of glass, of 6 1/2 inches diameter, and began to grind them to a spherical curve 12 feet radius.

I got them hollowed out, but failed in fining them through lack of skill.
This occurred six times in succession; but at the seventh time the polish came up beautifully, with scarcely a scratch upon the surface.
Stopping my work one night, and it being starlight, I thought I would try the mirror on a star.