378 Astronomy and Photography at Rome. 



of Jupiter and Saturn. Even all the recent improvements in ach- 

 romatic telescopes have proved insufficient, in the cold and thick 

 atmosphere of the northern division of Europe, to overcome the 

 intense radiance of the solar beams, forcibly reflected from objects 

 placed so near the Earth and the Sun as Venus and Mercury are. 

 The superior distinctness of telescopic observations in southern 

 latitudes was early experienced, although there appears to have 

 been an unwillingness to recognize the fact amongst the astrono- 

 mers north of Florence. Francisco Fontana, the Neapolitan as- 

 tronomer, was the first to discover the libration of the moon in 

 latitude, which had only been by analogy and in anticipation as- 

 serted by Galileo, who only detected the libration in longitude. 

 It was Fontana also, who first observed the spots on the discs of 

 Venus and Mars. By these he endeavored to ascertain the rota- 

 tion of those planets, and on November 11th and 15th, and De- 

 cember 25th, 1645, and on January 22d, 1646, delineated from 

 observation the phases presented by Venus. Like many others, 

 in advance of the age in which they live, Fontana did not obtain 

 the credence nor the credit which were his due. Riccioli and 

 Grimaldi both seem to have viewed him and his labors with the 

 eyes of rivals, and in their notice of his valuable discoveries, for 

 such they were, hesitated mistrust. The lapse of two hundred 

 years has at length brought a singular confirmation of the truth 

 of what Fontana asserted that he saw. Riccioli says, (lib. vii, 

 sect. 1, cap. 4.) — "In the observations of Francisco Fontana, 

 I read that Venus was seen in the evening through the telescope, 

 oblong, and about the same apparent size as the Moon seen with- 

 out a telescope, with a rough edge in the concave part, and send- 

 ing forth rays, especially when the figure was parabolic, and 

 (that which never hitherto has been heard of,) with one or two 

 dark colored round spots, at one time beyond, at another within 

 the body of the planet, so as to deform the disc, as may be seen 

 in the subjoined contracted sketches. If these things be true, 

 (for far be it from us to call in question the good faith of those 

 who affirm them,) it seems that we must say, that it was either 

 some meteor, perhaps a patch, pledget, or belt, or some small 

 cloud between the observer and Venus, or surrounding it ; or 

 that there are spots, like the solar spots, blown up, and as it 

 were bubbles from the body of the planet Venus, or like the cav- 

 erns and mountains of the Moon, more or less illuminated accor- 



