on the Planet Venus. 
H 9 
tainous inequalities and period of rotation which I formerly 
discovered, and partly the atmosphere and crepuscule of Venus, 
I. Remarks on the Mountains and Rotation of Venus. 
1. As I have already said, I gave, in the memoir on this 
subject published last summer, only those observations which 
particularly belonged to the object, out of a very great number 
that I had made during 13 years; and I omitted the rest, be- 
cause otherwise they would have amounted toa volume alone. 
Now with regard to those I have communicated, and which 
shew the real existence of considerable mountains, as well as 
an approximate determination of the rotation, the respectable 
author of the paper against me has not observed the planet 
Venus once at the same time , which might easily be the case in 
only 38 observations, that are adduced from a period of 15 
years. But in the numerous remaining observations, I saw 
neither mountains, inequalities, nor spots, any more than the 
author ; and I doubt not, that among these observations I 
should find many which were made at the same times as when 
he observed. The same holds good 
2. With respect to the new observations for three months,, 
here communicated, which amount to more than 100, and were 
made at yarious hours, and on different days. Of the 25 adduced 
by my opponent, there are only 4 made nearly at the same 
hour, which is the chief circumstance ; and not only in all 
these, but likewise in very many other observations, I saw, exactly 
as he did, no spot, and both horns like each other : so that of all 
his observations, not one contradicts mine. And yet it would 
