SQ Mechanical Philosophy. [Chaf. L 



ous Mr. GraPiam, before mentioned ; the Transit 

 and Equal Altitude Instrument, first made for le 

 Monnier, the French astronomer, by Mr. Sisson, 

 of London 3 and the Grand Astronomical Circle, 

 by the chevalier de Borda and others, the most 

 complete and comprehensive instrmnent in use 

 among astronomers, being in fact a kind of port- 

 able observatory, and probably carrying the deli- 

 cate accuracy of its indications to nearly as great 

 a length as human art will admit. Nor ought it 

 to be omitted here, that the method of graduating 

 astronomical instruments has, within the last 

 age, received the most astonishing improvements. 

 Mr. Bird, of London, was long distinguished in 

 this line ; but more recently his countryman, Mr. 

 Ramsden, has invented a method incomparably 

 more easy, expeditious, and accurate than any 

 before known. The abridgement of labour by 

 this new method is scarcely credible. An opera- 

 tion which cost Mr. Bird several days, we are 

 told, can now be performed much better upon 

 Mr. Ramsden's plan, and nearly in as many mi- 

 nutes. 



Beside the invention of new astronomical in- 

 struments, the last age is also remarkable for the 

 great improvement of almost all that were before 

 known, and in use. The services, by these means, 

 rendered to astronomy by the artists mentioned in 

 the hjGt paragraph, and also by Short, Graham, 

 Ilerschel, Troughton, M. Lenoir, and others, ai-e 

 too numerous and important to be adequately ac- 

 knowledged in this place. These improvements 

 have, no doubt, served great Iv to abridge the labour 



