ON THE CONSTRUCTION OF THE HEAVENS. 75 



advantage in commerce, but it is of ftill more benefit to the 

 refiner, by his operation being certain ; and he no longer runs 

 any rifque, if the calculations of his alloy have been accurately 

 made, of being ruined by unfuccefsful operations, and by the 

 neceflity of repeating two or three times a procefs of which 

 nothing can infure the fuccefs. 



III. 



Remarks on the Conftruclion of the Heavens. By William 

 Herschfl, LL. D. F. R. S, From the Fhibf. Tranj 'actions, 

 1802. p. 477*. 



IT has hitherto been the chief employment of the phyfical Celeftial objects 

 aftronomer, to fearch for new celeftial obj eels, whatfoever be^nXffed^ 

 might be their nature or condition ; but our flock of materials cording to their 

 is now fo increafed, that we fliould begin to arrange them ref P eftlve na - 

 more fcientifically. The claffification adopted in my catalogues, 

 is little more than an arrangement of the objects for the conve- 

 nience of the obferver, and may be compared to the difpofi- 

 tion of the books in a library, where the different fizes of the 

 volumes is often more confidered than their contents. . But 

 here, in dividing the different parts of which the fidereal hea- 

 vens are compofed into proper claffes, I fliall have to exa- 

 mine the nature of the various celeitial objects that have been 

 hitherto examined, in order to arrange them in a manner moll 

 conformable to their conftru&ion. This will bring on fome Introductory ob- 

 extenfive confiderations, which would be too long for the fervations « 

 compafs of a tingle paper; I (hall therefore now only give an 

 enumeration of the fpecies that offer themfelves already to our 

 view, and leave a particular examination of the feparate di- 

 visions, for fome early future occations. 



In proceeding from the mod fimple to the more complex 

 arrangements, feveral methods, taken from the known laws of 

 gravitation, will be fuggefted, by which the various fyftems 

 under confideration may be maintained ; but here alfo we fliall 

 confine ourfelves to a general review of the fubject, as obfer- 



* To this Paper is annexed " a catalogue of 500 new nebulae, 

 nebulous ftars. planetary nebulae, and clufters of liars," for which 

 the reader is referred to the Tran factions. 



vation 



