REFRACTORS ACHROMATIC 109 



on a large scale. Apparently the way here also 

 wan barred again*! progress. All attempt* to manu- 

 facture discs of pur.- Hint glam larger than seven inches 



Dimeter failed Up to that point the achromatic 

 refracting telescope was a great success. For seventy 

 years good specimens of considerable size were exceed- 

 ingly rare, and even in 1830 a disc of eleven inches and 

 seven-tenth- in 'immeter cost X1000. 1 An obscure 



inn, considering it probably impracticable to ex- 

 land the range of Doll end's telescope, or impressed by 

 the name and authority of Newton, wan amusing him- 

 f hard and continuous work can be called 

 amusement, with casting and grinding mirrors, with 

 mounting telescopes, and with studying the heavi 



gayest and idlest ,-l.m.l Th. 



people who formed the Literary Society of the town, 

 who met to read papers on scientific subjects, and some 



. >m were members of the Royal Society of London, 



iot even know him. They were pigmies ; a giant 

 was among them, of whose existence and works th< v 

 were not aware. 



The courage of this musician was extraordinary. In 

 the very year in which he removed to Bath, Messier, 



:ninent French astronomer, warned the Royal 

 Society nf 1 ,4>n.l. .n that progress in astronomy could 

 be hoped for only from refractors. His words are: 

 It were to be wished that astronomers might be 

 accommodated with achromatic telescopes of the most 

 perfect construction, as such are the only instruments 

 whereby a great knowledge of the celestial bodies can 



1 Hertchel sometime* uted a Si-feet achromatic or refracting tele- 

 cop* and a tingle eye-leu to confirm apparently the eridence of his 

 BtMb*tor7.f*et 



