Astronomy. 141 
Copernicus ; nor by Rheticus, in his celebrated tS 
thesystem of Copernicus; nor by Kepler, nor by eeioli, in in. hole 
po a of i me for and» against the heliocentric theory ; nor 
by Galileo, when announcing and commenting on the discovery of the 
pir sain what is most to the purpose, Miiler, in his excellent edi- 
tion of the great work of Copernicus, when referring to the discovery 
of the phases of Venus, as made since; and unknown to, Gaperniop 
Copernicus. If we try to examine what the opinion. of age nia * 
this matter really was, a point of some little curiosity arises. It 
on one word, whether he did or did not assert his belief in one-or other 
.of these two cee 9 apray the planets shine by their own. light, or 
that they are'sat rated by the’solar light, which, as it were soaks through: 
them. I cuapist the affirmative: that is ota I hold it suffiei 
certain that Copernicus did express. himself to —_ that one or 
these suppositions was the trut 
if we cients: first edition of the work De-Revolutionibus, hich was 
the manusc by “— himself, there is 
little doubt about the matter. There are but tw 0 passages Ww whieh bear : 
thé question. The first is in the ad lectorem, in-which 
the writer (Osiandery though even Delambre make him Copernicus) asks 
whether any one acquainted with geometry or optics can receive the 
Ptolemaic epicycle then used to explain the motion in longitude of Ve- 
nus? But the meaning ofthe allusion to-opties is explained i in the next 
nee, by a reference (and by no means e-firipmade deve} tot 
arent diameter of Venus derived from. the epicycle ; =) pres. 4 
yhich, ‘as they made the perigean diameter more than four ti 
ed 
the dificulty a arising from. the absence of the nate ibe ghianes whioh 
We now call the transit over the sun’s disc. He describes the opinion | 
just mentioned favorably, referring, not to his own view, but’to that of 
those others who had held it. This is not an uncommon idiom: per- 
sons advocatipg an unpopular opinion are very apt to describe the main- 
tainers of it in the thitd person, though themselves be of the number. 
when he comes to describe what he takes to be the necessary ¢on- 
sequences of the opinion, he lapses into the first person as follows = 
“Non ergo fatemur in stellis opacitatem esse aliquam lunari similem, 
sed vel proprie:I lumine, = aoe totis imbutas corpedpe ful et 
idcirco solem 
These are ie iorde oP first eden (Nuremberg, 1543), 
Copernicus could have answered any objection, either by word or write ' 
impossible, sinee he drew his last breath within a few of 
g 
aa, Sage Jigs aclby is aM ela oad ae male sa a oe 
