120 Mr. Schroeter's new Observations . 
and the author had compared the almost innumerable and va- 
rious observations contained in it, which all agree in their re- 
sult, he would never have made such a declaration. I have 
myself also never actually seen mountains in Venus as in the 
moon, but only deduced their existence and height from the 
observed appearances. It is even impossible to see them, ac- 
cording to what I have expressly asserted in my paper on the 
Twilight of Venus ; because, on account of the thickness of 
her atmosphere, we can never perceive the shades of land on 
her surface. But if the appearances observed by me and others 
are true, the result deduced from them js mathematically 
evident. 
That I have seen, not unfrequently , the boundary of illumi- 
nation irregular, is nothing new , nor does it afford me any fur- 
ther merit than that of confirming with many others, an old 
truth , which de la Hire, and still more ancient good astro- 
nomers, provided with the best and most powerful telescopes 
of their kind, had long ago discovered in perfectly similar 
phenomena. So early as the year 1700, de la Hire observed 
greater inequalities in the termination of light in Venus, than 
in the moon ;* and the Paris Academy thence concluded that 
planet to have higher mountains. The sole addition, as far as 
I know, which I have made to the older observations is, that 
in the crescent phase of Venus, sometimes one horn is only 
half as broad as the' Other; and that sometimes, though not 
often, about the period of the greatest elongation, one end of 
the enlightened part appears pointed, but the other rounded 
off: appearances which others, who had not been apprized of 
what they were to see, have frequently perceived as well, and 
* See Memoires de l’ Acad. desScienc. 1700, p. 378. 
