376 HISTOEY OF ASTEONOMY. 



solved 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 Philosoph- 

 ical 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. He then proceeded to the 

 manufacture of refracting telescopes, but being dis- 

 couraged by the difficulty of obtaining suitable glass, 

 he turned his attention to reflectors. In this he sue?- 

 ceeded remarkably Well, and now his telescopes are 

 found in almost every State of the Union, and some 

 have been ordered for foreign countries. Mr. Holcomb 

 now manufactures four sizes of instruments. 



The first size is 14 feet long and 10 inches aperture, 

 with six eye-pieces, magnifying from 100 to 1000 

 times. 



The second size is 10 feet long and 8 inches aperture, 

 with six eye-pieces, magnifying from 60 to 800 times. 



The third size is 7j feet long and six inches aperture, 

 with five eye-pieces, magnifying from 40 to 600 times. 



The fourth size is five feet long and four inches aper- 



