TIBGINIS BY THE MOON. 181 



a particular communication, but when it is regarded in connection 

 with some unusual, though not unprecedented appearances seen in 

 the occultation of the star Spica at the same time, and it is con- 

 sidered that possibly the same optical or atmospheric causes may- 

 have exercised more or less influence on both phenomena, I have 

 been induced to bring both matters before the Institute. 



With reference to the planetary look of the stars, of the 1st 

 and 2nd magnitude, as observed by me on the night of the 12th 

 March, (a night not easily forgotten, having been that on which the 

 terrible railroad accident occurred at the Desjardins Canal bridge.) 

 I saw that bright star in Lyra, (Vega,) with a disc like the planet 

 Jupiter ; this was about one o'clock on the morning of the 13th. I 

 could scarcely believe it was not a new star, so brilliant was its ap- 

 pearance, till I satisfied myself of its identity ; I then observed the 

 other stars of the 1st and 2nd magnitudes which were visible, viz. 

 Arcturus, Regulus, Procyon, Castor, Pollux, and Capella; and all 

 of these presented the same marked planetary appearance, with an 

 absence of scintillation, and altogether different from the ordinary 

 look of these stars- The moon was shining bright — being only 

 two days past the full ; the night was cold and frosty, but perfectly 

 calm ; the stars resembled the appearance they exhibit in the tropics 

 as described by Humboldt, who says, referring such appearances to 

 atmospheric causes : " thus the more equal mixture of the atmos- 

 pheric strata in and near the tropics, and that faintness or total 

 absence of scintillation of the fixed stars, when they are 12 or 15 

 degrees above the horizon, give the vault of heaven a peculiar 

 character of mild effulgence and repose. Cumana and the rainless 

 portion of the Peruvian Coast of the Pacific, were peculiarily suited 

 for such observations ; on the average, the fixed stars appear only to 

 seintill ite when less than 10 degrees above the horizon, at greater 

 elevations they shed a mild planetary light," &c. And again Hum- 

 boldt says, quoting another author's remarks, speaking of the 

 climate of Arabia : " the light of the stars is pure, steady, and 

 brilliant ; and it is only in the middle of winter that a slight degree 

 of scintilliation is observed." All this, however, is very different from 

 the general look of the starry vault in Canada, where on cold and 

 frosty nights the stars twinkle continually ; and where even in 

 summer the planetary look is wanting. 



Some stars, however, by an inherent property in their light, 

 twinkle more than others. Humboldt says Vega is perhaps one of 

 the stars which twinkles the least ; Arcturus and Capella also 



