REMARKS 



TWINKLING OF THE STARS 



BY JOHN BLACKWALL, F.L.S. 



(Read October 5th, 1827.) 



oO numerous and contradictory are the hypo- 

 theses in which men of science have indulged, 

 relative to the cause of the twinkhng of the stars, 

 that hasty and superficial inquirers are frequently 

 induced to regard them merely as the fanciful 

 conjectures of speculative theorists ; but this con- 

 clusion, if correct in particular instances, will 

 not, I am persuaded, be found so in all. 



The ingenious Robert Hooke, so long since as 

 the year 1665, attributed the phenomenon of 

 twinkling to the unequal and inconstant refrac- 

 tion of, the rays of Hght, occasioned by the 

 trembling motion of the air and interspersed 

 vapours, in consequence of variable degrees of 

 heat and cold in the air, producing corresponding 



