l5S On the Quejiion, whether the Sim, Mooiij ani 



quent obfervations of the fpots and faculse, we fliall be able 

 to obtain a chart of the fun, as we have obtained one of the 

 moon : for, according to this hypothefis, the fpots of the fun 

 are not clouds and thick vapours that arife from the opaque 

 bodyof the folar orb. According to Peyroux de la Coudreniere, 

 all the planets are ftill approaching nearer to the nature of 

 the fun ; and, in his opinion, Venus, Jupiter, and Saturn, 

 would not exhibit fuch a luminous appearance were they en- 

 lightened merely by the fun. He concludes, therefore, that 

 abundance of inflammable vapour muft afcend into their at- 

 mofphej-es, and, by taking fire, increafe their light. Ac- 

 cording to him, our earth acquires a confiderahle light from 

 a like caufe : and this indeed is not altogether improbable; 

 for I myfelf, with a telefcope of a great magnifying power, 

 have frequently obferved the heavens, by day as well as night, 

 for this purpofe alone, and have feen, in a quarter of an hour, 

 a 2:reat many inflammations of this kind in the atmofphere. 

 Peyroux de la Coudreniere, however, goes t'oo far when he 

 believes that Saturn, the remotefl; of the planets, feemsas if 

 inclinincr to remove from our fyflem altoo-ether ; to convert 

 himfelf into a fun, and to have planets revolving around 

 him. This conceit is fufficicntly refuted by the difcovery of 

 Uranus (the Georgium fidus) by Dr. Herfchel. 



Upon the whole, we have no certain grounds on which 

 we can reafon refpefting the atmofpheres of the planets. 

 Becaufe our earth has one, and is a planet, it docs not thence 

 follow that the re(t muft have atmofpheres. We indeed fiud 

 every where in nature the grealelt diverfity and variety; and 

 if we always formed conclufions from analogv, we fliould fall 

 into the greatell abfurdities and errors. 



M. Schrdter, from the alternate obfcurity and bright ap- 

 pearance of Jupiter,- which he has obferved, thinks himfelf 

 authorifed to conclude, that the atmofphere of .lupiter, in 

 general, has a great fimilarity to ours*. It is very remark- 

 able, adds he. that the whitifh and light zones are not al- 

 ways perfcftly brisrht, but in common feem to be covered 

 with a thin atmofpheric matter, and to have fometimes a 

 more luminous appearance than at others. It is not imprOf 

 * See \i\^BtjUS^e. zu den ajlrommijcben entdeckun^cn , Berlin 1788. ^v"). 



bable 



