72 Alechanical Philosophy. 



delicate accuracy of its indications to nearly ais 

 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, receiv^ed the most astonishing im- 

 provenients. Mr. Bird, of Great-Britain, 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. TJie abridge- 

 ment of labour by this neW method is scarcely 

 credible. An operation which cost Mr. Bird 

 several days, we are toldj can now be performed 

 much better upon Mr. Ramsden's plan, and 

 nearly in as many minutes. 



Besides the invention of new astronomical in-^ 

 struments, the last age is also remarkable for the 

 great improvement of almost all which were before 

 known and in use. The services, by these meansy 

 rendered to astronomy by the artists mentioned in 

 the last paragraph, and also, by Short^^ Gra-^ 

 HAM, Herschel, Troughton, and others, among 

 whom might be mentioned several French artists 

 of eminence, are too numerous and important to 

 be adequately acknowledged in this place. These 

 improvements have, no doubt, served greatly to 

 abridge the labour of astronomical caleTulations, 

 and to confer new accuracy upon every part of 

 the science. 



At the conclusion of the seventeenth century,- 

 the number of regularly established and endowed 

 public Observatories was small. It is believed 

 that only tzvo, or at most th?^ee, of any distinction 

 existed on earth. Within the last century, the 

 number of these institutions has greatly increased^ 

 They are now established in almost every part of 

 Europe; richly furnished with the best apparatus 

 for making observations; and continually sending 



