36 HERSCHEL AND HIS WORK 



forgotten. In the last year of her life, when visited by 

 the Crown Prince of Hanover, his wife and child, she 

 sang to them a composition of her brother William's, 

 "Suppose we sing a Catch." The gulf between 1780 

 and 1847 was at once beautifully bridged by the little 

 old lady of ninety -seven ! 



Dollond had shown in the Philosophical Transactions 

 for 1758 how the colours, that rendered a refracting 

 telescope useless as a means of discovery, might be 

 obviated. He pointed out to his countrymen how flint 

 glass and crown glass corrected each other's defect, and 

 might be used, as they had never been used before, to 

 search into the depths of heaven. It was a marvellous 

 discovery; but thought in those days was perhaps 

 slower of action than it is now, for a seed of truth, 

 laden with immense possibilities, lay dying in the 

 ground for sixty years, till Fraunhofer of Munich 

 applied it to construct the great refractor of Dorpat. 

 But it was reflecting telescopes of the Newtonian and 

 Gregorian pattern, not refractors such as Dollond's, to 

 which the enthusiast of Bath finally turned his atten- 

 tion. What Gregory and Newton had proposed or 

 executed on a small scale, Herschel proceeded to build 

 with his own hands on a vastly larger, after finding 

 that the cost of even a small telescope would be above 

 the price he " considered it proper to give." It was not 

 a case, as might be supposed, of the narrow insularity 

 of our countrymen thus to neglect a great discovery 

 by following out a more cumbersome English method. 

 Gregory, Newton, Dollond all belonged to this country. 

 It was also the adopted home of Herschel, but he pre- 

 ferred the toilsome telescopes of the two former to the 

 simpler and now possible instrument of the latter. 



