Astronomy and Photography at Rome. 379 



ding to their varying position with respect to the Sun, or perhaps 

 owing to the rotation of Venus on its axis, or to its libration ; for 

 neither dare I say that Venus has satellites, until the day come 

 that may teach us something more certain concerning this affair. 

 It has never certainly been permitted for me, nor for Father Gri- 

 maldi, nor for Gassendi, as appears by the 3d book of his Institu- 

 tions of Astronomy, to see in Venus, nor near Venus, those small 

 globes (or spots) by means of any telescope," 



So said the Father Riccioli two hundred years ago ; remarks 

 certainly not very encouraging to the communicators of new dis- 

 coveries. But time, the vindicator, has at length done his work ; 

 and long after Galileo, Fontana, Riccioli, Gassendi, and Grimaldi 

 have ceased from their watchings and their labors, and enjoy 

 their rest, " unmindful of the call of the morning," the controvert- 

 ed points have come to be resolved : 



u Omne, quod optanti divom promittere nemo 





Auderetj volvenda dies, en attulit ultro." 



The four delineations given by Fontana, correspond closely 

 with the account given by the Roman astronomers, in the memoir 

 now under discussion. In Fon tana's delineation of the appear- 

 ance of Venus on Nov. 11, 1645, the disc is rather more than the 

 quarter, and has an oblong dark spot in the middle of the illumi- 

 nated part ; in that of Nov. 15, 1645, the disc is nearly the half 

 section, with the ragged edge on the concave side, and dark de- 

 tached spots at each horn of the crescent ; in that of Dec. 25, 1645, 

 the disc is gibbous, and has only one dark detached spot on the 

 lower horn ; in that of Jan. 22, 1646, the disc is a crescent near- 

 ly filled, and with a dark oblong detached spot right in the cen- 

 tre of the concave boundary. 



The Roman astronomers inform us that Venus was observed 

 by them on April 32, 1841, at six of the evening; that "the 

 phase presented by the planet was rather small, and that near the 

 point of the northern horn, and properly in the middle of the illu- 

 minated part, there was seen very plainly a dark oblong spot. It 

 appeared as if a short and fine thread of black silk were placed 

 so as to lie on that part. Whilst the usual observations were 

 making of the diameter of Yenus, the Signor Clemente Palomba, 

 the assistant observer, to whom was entrusted the care of the in- 

 strument and of the micrometricai observations, gave us notice 





