SECTION VI

Summary

Various attempts have been made in this country to manufacture both reflecting and refracting telescopes. I shall speak of each of them in succession.

REFLECTING TELESCOPES.

A great many reflecting telescopes have been constructed by amateur astronomers in different parts of the country; but, for the most part, these attempts have been but moderately successful, and have contributed but little, if any thing, to the progress of science. The most important exception to this remark was in the case of a telescope manufactured in 1838, by Messrs. Smith, Mason and Bradley, the two former gentlemen being at that time students of Yale College. This telescope had an aperture of twelve inches, and a focal length of fourteen feet. The mirror was cast, ground, and polished by their own hands. Stars of less than one second's distance, were separated by this instrument; the faint star, “debilissima,” near ε Lyræ, was easily shown; and the nebula in Hercules, between η and ζ, was resolved into an immense number of small stars. With this instrument, Mr. Mason made some very accurate observations of three nebulas, of which an account is given in the Transactions of the American Philosophical Society. This paper affords but a foretaste of what might have been anticipated from the talents of Mr. Mason, had not his course been arrested by his premature death, which occurred Dec. 26th, 1840.

Several mechanics have undertaken the manufacture of reflecting telescopes for sale, but the only one who has pursued this business to any great extent is Mr. Amasa Holcomb, of Southwick, Massachusetts. Mr. Holcomb first attempted the grinding and polishing lenses about the year 1826.