380 HISTORY OF ASTRONOMY. 



1814, lie returned to Brenets, and established a separate 

 manufactory, where he made telescopes, and furnished 

 both flint and crown-glass. In 1823, he was able to pro- 

 duce a disc of a foot and a half in diameter. In 1824, he 

 exhibited at the exposition of industry at Paris, a grand 

 achromatic object-glass, which excited the admiration of 

 the king, who solicited the son of Guinand, then present, 

 to invite his father to take up his residence at Paris. 

 Unfortunately, the optician was not in a condition to 

 remove. He died in 1825, at the advanced age of nearly 

 80 years. 



Another individual who contributed to the reputation 

 of the establishment of. Keichenbach, perhaps even more 

 than Gruinand, was . the illustrious Fraunhofer. Fraun- 

 hofer was born at Straubing, in Bavaria, in 1787, and at 

 twenty years of age (in 1807) was received into the man- 

 ufactory of Eeichenbach. He here exhibited the most 

 extraordinary talents, and introduced many improve- 

 ments into the manufacture of glass, as well as in the art 

 of polishing the spherical surfaces of large object-glasses. 

 His crowning glory was the manufacture of a telescope of 

 nearly ten inches aperture, which was purchased for the 

 observatory of Dorpat, in Eussia. 



It has been asserted that the object glass of the Dorpat 

 telescope was made from glass cast by Guinand; but 

 this has been positively denied by Utschneider, who 

 states that the glass for the Dorpat telescope was cast 

 by Fraunhofer, after Guinand left the establishment at 

 Benedictburn ; and he also states that the glass which 



