Por fe 
II. On, the Nature and est BO of the Sun and F. ‘edd 
Stars. By Witttam Herscue., LL.D. F.R.S.* 
Aone the celeftial bodies, the Sun is certainly the 
firt which fhould attra& our notice. It is a fountain of © 
lizht that illuminates the world! It is the caufe of that — 
heat which maintains the productive power of Nature, and 
makes the earth a fit habitation for man! It is the central 
body of the planetary fyfiem; and what renders a know-_ 
ledge of it {till more interetiing to us is, that the numberlefs 
ftars which compofe the univerfe, appear, by the ftriéteft ana- — 
logy, to be fimilar bodies. Their innate light is fo intenfe, 
that it reaches the eve of the obferver from the remoteft re- 
gions of {pace, and forcibly claims his notice. 
Now, if we are convinced that an enquiry into the nature 
and properties of the fun is highly worthy of our notice, we 
may alfo, with great fatisfaction, reflect on the confiderable 
-progrefs that has already been made in our knowledge of this 
eminent body. Tt would require a Jong detail to enumerate 
all the various difcoveries which have been made on this 
fubjeét; I fhali therefore content myfelf with giving only. 
the moft capital of them. 
Sir Tfaac Newton has thewn that the fun, by its attractive: 
power, retains the planets of our fyftem im their orbits: he 
has alfo pointed out the method whereby the quantities of 
matter which it contains may be aceurately determined. Dr. 
Bradley has afliyvned the velocity of the felar light with a 
“degree of precilion exceeding our utmoft expectation, Gal- 
lileo, Scheiner, Hevelius, Caffini and others have afcertained 
ithe rotation of the fun upon its axis, and determined the po- 
fition of its equator. By means of the tranfit of Venus over 
«the difk of the fun, our mathematicians have caleulated it 
ediftance frem the earth; its real diameter and magnitude 
the denfity of the matter of which it is compofed; ‘and th 
fall of heavy bodies on its furface. 
* From the Pailofophical Tranfadlions of the Royal Society for 179 
Part [. 
