36 Star ant) TOeatber Gossip 



even a suspicion of vivacity. But " leaden " as 

 Saturn may appear, it is a flimsy enough body after 

 all ; perhaps no heavier than cork. 



I nave sometimes wondered if the twinkling of a 

 planet is to any extent affected by the outer envelope 

 of the body. Mercury, for all we know, has an exterior 

 covering of dense cloud, and Mercury's light flickers 

 with a truly bewildering rapidity. Venus, too, has a 

 thick cloudy veil, and that planet, also, twinkles with 

 great vigour, at times. Mars possesses a very rare 

 atmosphere, and my observation shows me that it 

 twinkles in but one particular position. Jupiter, of 

 more or less gaseous constitution, throbs a little now 

 and again, and Saturn, which seems to be largely 

 gaseous, remains immobile. Yet the stars are gaseous, 

 and they twinkle the more the lower they get. Of course, 

 a star's point of light is more susceptible of atmos- 

 pheric interference than is the visible disk of a planet. 



Perhaps the colour of a planet is a factor to be 

 considered in regard to scintillation. Colour seems to 

 be of account where the stars are concerned. Then, 

 I have often observed that a planet will twinkle the 

 more vigorously, the more it is immersed in the sun- 

 light, compatible, that is, with its visibility with the 

 naked eye. Venus and Jupiter, for instance, have 

 always appeared to me to be unsteadier when setting 

 just after the sun or rising just before that body. The 

 twilight or the dawn-light, indeed, would seem to have 

 a singular effect upon the light of both stars and 

 planets, such of them, at any rate, as are at a low, or 

 fairly low altitude. 



I have seen Sirius scintillating in the twilight as if 

 it would leap out of the sky. 



