Mr. Schroetep/s Observations 
S 3 6 ’ 
strong light of Venus must occasion a much greater degree of 
glare, than the soft light of the moon in a much more rarified 
atmosphere. In general it appears to me, that whoever will 
bestow some attention on these observations, and compare them 
impartially with the many others I have made on the atmo- 
spheres of the moon, Jupiter, Saturn, and even the sun, will 
find a striking coincidence between them. 
The simple fact, that Venus in its different phases, and es- 
pecially at the times of its greatest elongations, shews a much 
greater diminution of light at its terminating border than the 
moon, is, no doubt, sufficient to point out a much denser at- 
mosphere than that of this satellite. And this is, moreover, 
fully evinced by the observations on its twilight. The circum- 
stance also, that there are seen on this planet none of the flat 
spherical forms as are conspicuous on Jupiter and Saturn, none 
of the stripes or longitudinal spots parallel to the equator, 
which are seen on these planets and the sun, and which point 
out a certain stretch of atmosphere, gives room to infer, that 
the globe of Venus, with reference to its diameter, and other 
circumstances of physical arrangement in its construction,* 
performs its rotation round its axis in a much longer space of 
time than those planets, or the nearly similar ones of our earth 
and Mars ; and this is actually confirmed by my observations 
on the diurnal period of Venus. 
Thus we see a remarkable coincidence in every respect ; and 
yet, though we cannot suppose a smaller, but rather a greater 
force of gravity on the surface of Venus than on our globe, 
* These references have already been noticed by Chevalier de Goimpy, in the 
Journal des Savans for January, 1769; and before him, by M. de Mai ran, in the Me - 
moires Acad, for 1729. SeeDe la Lande’s Astron. §. 3219, and 3122. 
