ASTRONOMICAL HISTORY. 177 



sufficiently authenticated facts on the subject, as when 

 the sun three several times, without the occurrence of an 

 eclipse, or the intervention of clouds, appeared in a clear 

 and serene sky, changed in appearance for many days, 

 and yet not affected in the same way each time, being 

 once of slender light, and twice of a ferruginous colour. 

 For these phenomena took place in the year 790, during 

 seventeen days, and in the time of Justinian during half a 

 year; and after the death of Julius Caesar, during several 

 days. To that obscuration we have still extant that noted 

 testimony in Virgil : 



Ille etiam extincto miseratus Caesare &quot;Romam 

 Cum caput obscura nitidum ferrugine texit, 

 Impiaque eternam timuerunt saecula noctem. 



And the statement of Varro, a most skilful antiquarian, to 

 be found in Augustine respecting the planet Venus, to this 

 effect, that in the reign of Ogyges it changed its colour, 

 size, and figure, might well have been doubted, had not a 

 similar fact occurred again, signalised by much observa 

 tion in our own days, in the year 1578. For then, too, 

 during a whole year, a memorable change took place in 

 the planet Venus, which was seen of unusual size and 

 brilliancy, exceeding in redness even the planet Mars, and 

 more than once changed its figure, becoming sometimes 

 triangular, sometimes square, and sometimes circular, so 

 that even its very body and substance seemed to be affected. 

 Again, that star among the old stars, placed in the hip 

 of Canicula, which Aristotle says he himself saw, having 

 some coma, which he particularly noted, vibrating when 

 he looked at it intently, appears to be since then changed 

 and to be divested of its hair, since no trace of that appear 

 ance is found on it in our day. Add to these facts that 

 many alterations of the celestial bodies, particularly of the 

 smaller, from neglecting to make observations, easily escape 

 notice, and are lost to us. Now it will readily occur to a 

 sciolist to ascribe such appearances to exhalations and the 

 constitution of the medium of vision ; but these alterations, 

 which are found to affect such a body continuously and 

 equally for a considerable time, and to accompany it in its 

 revolutions, ought to be placed altogether to the account 

 of the star itself, or at least something in the ether con 

 tiguous to it, not in the lower tracks of the air ; of which 

 we may assume this as a strong argument, that such changes 

 rarely occur, and at long distances of years, but those 

 which take place in the atmosphere by the interposition 

 VOL. xv. N 



