ASTRONOMICAL INSTRUMENTS, 



GLOBES. 



Eighteen inch Globes of the Society for the Diffusion of 

 Useful Knowledge. (Fig. 115, next page.) In these globes 

 an endeavor has been made to combine a degree of accu- 

 racy, such as is only possessed by the best modern maps, 

 with the lowest price at which excellence can be attained. 

 The terrestrial globe has been compiled from the most recent 

 geographical surveys, with the aid of the accounts given by 

 the best travellers; and there is annexed on the 18-inch 

 globe a table of the population of the different countries in 

 the world, compiled from the latest official returns, and, 

 where these are wanting, the best authorities which could 

 be obtained by Mr. G. 8. Brent, Fellow of the Statistical 

 Society of London. 



The astronomical information which has been supplied 

 of late years upon the position and nomenclature of the 

 fixed stars, has rendered a perfectly new celestial globe a 

 most desirable acquisition to the student of astronomy. 

 The labors of Piazzi, Bradley, Lacaille, Johnson, &c., in de- 

 termining the places of the stars, and those of Baily in the 

 correction of their nomenclature (in the new edition of the 

 " British Catalogue"), have been carefully consulted in the 

 celestial globe which is now advertised. The stars in the 

 northern hemisphere are all which are given by Piazzi, with 

 the addition of such of Bradley 's (from the Tabulae Regio- 

 montanae) as are not in Piazzi. The stars in the southern 

 hemisphere comprise all those given by Lacaille and Johnson. 

 The magnitude of each star is that by which it is designated 

 in the catalogue from which its place is taken : and the 

 several orders of magnitude are so distinguished from each 

 other as to be read, after a little practice, without the ne- 



