C *8 ] 
reality not ignited. But, from the nature of the 
thing, doth there feem any neceffity for thinking, 
that there prevails there any fuch raging and fer- 
vent heat, as many have imagined ? It is proper 
here, to attend to the diftin&ion betwixt this 
fliining matter of the fun, and the rays of light 
which proceed from it. It may perhaps be thought, 
that the re*aCtion of the rays upon the matter, at 
their emifhon, may be productive of a violent 
degree of heat. But whoever would urge this ar- 
gument, in favour of the fun being intenfeiy heated, 
as arifing from the nature of the thing, ought to 
confider, that all polifhed bodies are lefs and lefs 
difpofed to be heated, by the aCtion of the rays of 
light, in proportion as their furfaces are more po- 
lifhed, and as their powers of reflection are brought 
to a greater degree of perfection. And is there not 
a ftrong analogy betwixt the re-aCtion of light upon 
matter, in cafes where it is reflected, and in cafes 
where it is emitted ?- 
It may perhaps be expeCled, that, in this paper,, 
mention fhould be made of the other appearances, 
that are difcernible upon the furface of the funy 
befides the fpots properly fo called; I mean the fa* 
culre, luculi, &c. as defcribed by Scheiner and He* 
velius. But all thefe phenomena feem to be fo 
different from any thing we have confidered, and 
fo unconnected with the prefen t difeovery, that 
little affiftance can be brought from that quarter 
towards a right conception of them. As to the 
faculae, or brighter parts of the fun, we are at a 
lofs for their origin. It may in general be re* 
marked', that although we have obtained an expe* 
rimentah 
