ON THE NATURE OF THE SUN. 13 



it as preferable to the repetition of the obfervations ; which 

 procefs muft, for many reafons, have the advantage over any 

 mechanical contrivance vvhatfoever. 



I have procured reflecting circles to be conftructed, upon The Invention 

 the principles here defcribed, both with the telefcope and the [" c c e " eds ln prac " 

 horizon glafs upon a moveable index, and with the , fame 

 pieces attached to the main frame of the inftrument. The 

 two methods have refpectively anfwered my expectation ; and 

 I purpofe, at a future opportunity, to publim a defcription of 

 the means which I with to recommend for the mechanical 

 improvement of the different parts, together with an account 

 of fome other eflays which I have made relative to the fame 

 fubject. 



III. 



Obfervations tending to invejiigate the Nature of the Sun, in order 

 to find tfte Caufes or Symptoms of its variable Emijion of Light 

 and Heat; with Remarks on the Ufe that may pojjibly be drawn 

 from Solar Obfervations. By Wi t L i a m H e r s c h e l , LL. D . 

 F.R.S.* 



N a former occafion this eminent aflronomer gave his The fun Inferred 



reafons for inferring that the fun is a moft magnificent habitable *£» habitabk 



globe In the prefent paper he proceeds coniiderably farther 



in the inveftigation of the phyfical and planetary conftruction 



of that luminary. He introduces his fubject by remarking, 



that the influence of this luminous body on the globe we in- its Influence of 



habit is fo great and fo widely diffufed, that it becomes almoft the S reateft im - 



° . . • portancc to us, 



a duty for us to ltudy the operations winch are earned on at 



its furface ; that from motives arifmg from the important and deferves to 

 effects of light and heat we ought certainly to examine their be ftudlcd « 

 iburce, and though, like the Egyptians with the Nilometer, 

 or modern philofophers in their obfervations upon the atmoi- 

 phcric phenomena, we can entertain no hope of modifying 

 the effective caufes, yet, by arranging the particulars of 

 our own conduct by the foreknowledge of events though 

 inevitable, we may add much to the general felicity and en- 

 joyments of fociety. • • - 



# Abridged from the Philofophical Tranfaaions f 1801, p. 265. 



W. N. 

 Dr. 



