ASTRONOMICAL NOTES. 295 



If personal equation in the estimation of colours, and the 

 influence of different appertures could be disregarded, we have here 

 clear evidence of a star- changing its colour from red to white, in a 

 period of eighteen years, but my own experience inclines me 

 to accept any such deduction with caution — although had this series 

 been made by one experienced observer the evidence would have 

 been strong in favour of change. 



95 Herculis. 



This double star deserves careful attention, from its suspected 

 change of colour. 



Its normal tints are Pale Orange and Pale Green, or, as Admiral 

 Smyth calls it, Cherry Red and Apple Green,* but in his " Sidereal 

 Chromatics ' ' he considers that it undergoes marked variations of 

 colour, and, that the evidence he brings forward completely proves 

 this, the most remarkable instance being the observations of Captain 

 Higgens, of Bedford, made with a 4-inch Cooke Refractor, in 1863, 

 when the stars changed from white to the normal tints in the 

 three months from May to August. Sir G. B. Airy suggested that 

 the simultaneous change for the two stars is suspicious, and looked 

 like a possible change in the telescope, and Franks states that most 

 subsequent observations confirm Smyth's colours. f 



There is, however, further recent evidence of colour change in 

 this star. In August, 1885, I noted this pair as being both silvery 

 white 5 on September 13th, both yellowish white, with no difference 

 of colour between them ; on September 24th, both same tint, very 

 pale yellow, certainly not white ; but on October 4th, the colours 

 were very pale yellow, very pale green, with a noticeable contrast 

 of colour between them. 



Throughout the present year the tints have been the normal 

 ones — pale orange and pale green. 



The foregoing observations were made with the Taunton 

 Refractor of 3|-inches aperture, by Cooke & Sons. 



H. MICHELL- WHITLEY. 



*A Cycle of Celestial objects, 2nd ed., p. 509. 

 f Astronomy for Amateurs, p. 259. 



