174 Mr. Schroeter’s Observations 
favourable circumstances , streaked with shade , exhibiting an 
irregular arch of termination, with indented spots, unequal 
horns, and so forth. I shall, therefore, at least till adequate 
reasons convince me otherwise, never assent to a bare hypo- 
thesis, that in this planet we merely see its atmospherical 
cover, and never the body itself ; unless when, very rarely, 
a clearing up of its atmosphere allows us to get sight of a 
small part of its real surface, in the dark form of a cloud-like 
spot. 
Finally, as to what the celebrated author has remarked 
besides, on the apparent diameter of Venus, in the mean distance 
of the earth; namely, that by a mean of the measurements 
he made Nov. 24th, 1791, with the 20-feet reflector, it amounts 
with great certainty, to 18", 79; and that therefore the planet 
is larger than it has been given by astronomers hitherto: 
this is a matter which belongs only indirectly to my object 
here. 
I could have wished that he had not depended too much on 
a single instrument, having an excess of light, in which the 
irradiation may unobservedly extend further than in weaker 
telescopes, nor on a single micrometer ; but had reduced his 
mean from many measurements, made with various and less 
powerful telescopes, and on many days, under very different 
apparent diameters, in order to his conclusion for the mean 
distance of the earth ; because, as I only observe here pre- 
viously, for want of room, I doubt very much of the depen- 
dence to be placed on those measures ; and must consider this, 
at least, as rather too large, until I can convince myself of the 
contrary. 
Comparing this determination with that which has been 
