«208 0N COMETS. 



but rather of f or tl)e bod of the g un itse]f j t mugt be a j^ of mpQur 

 a stm j>:i of vi- V 



clouds. which, emanating incessantly from the Sun, always rises 



to the same height in its atmosphere, and there forms a 

 stratum as it were of clouds, which is decomposed at a 

 certain height, like, the luminous clouds that are sometimes 

 formed in our atmosphere. By this decomposition the light 

 escapes ; and the substances, with which it was combined, 

 must form some kind of dew, that falls back again upon the 

 v pots rat e g un> Row the transparent spaces, through which we see 

 the opake body of the Sun, are parts of,its atmosphere, 

 into which the luciferous vapour does not ascend, or where, 

 when it arrives there, it does not find the ingredients neces- 

 sary to decompose it into clouds. The latter case would be 

 Openings be- analogous to what we see take place in our own atmosphere, 

 clouas when through the intervals of the clouds we discern the blue 



colour of the transparent air. The matter of clouds is 

 there, since, as I have proved, they are formed by the de- 

 composition of the air itself; but in these spaces the ingre- 

 dient, which decompose the air, and which assuredly rises 

 from the Earth, is not present. 

 The same the- This theory of the luminous effects of the Sun maybe 

 to\>XVceles° applied directly to the fixed stars ; and it may also be ex- 

 tul bodies, but tended to other large bodies with some modifications. The 

 ideations aimos P ner i c effects of every one of the bodies dispersed 

 through space depend on its particular constitution. To 

 the constitution of the Sun and fixed stars are owing the 

 greatness and constancy of the luminous phenomena, by 

 which they are distinguished. But other bodies, from the 

 difference of their constitutions, may produce phenomena 

 of a similar kind, though much inferior in different degrees, 

 more or less rarely, and under different appearances. Our 

 Earth, though of the lowest order in this respect, maintains 

 its analogy by the phosphoric phenomena of its atmosphere ; 

 and there may be many intermediate degrees between the 

 highest and this, the lowest. 

 Cotoet* From this last consideration has arisen my conjecture 



respecting the nature of come ts ; but to establish it de- 

 mands at least a knowledge of every thing, that has been 

 observed respecting these bodies, which I have not studied. 

 What I have the honour to lay before you therefore, Sir, 

 * you 



