286 Proceedings of Societies. 
Prazzi Smytu.—The star 95 Herculis is a double star, of which the two 
members are nearly of equal magnitude, about the 5th, and are six 
seconds apart, in R.A. 17h. 55’ 33” and D 21° 25’ 56” in 1860. It 
has hitherto been catalogued as a diversely coloured pair of stars to an 
extreme degree, one member being called ‘apple green” and the other 
“cherry red.” These colours have moreover been looked upon, as are 
the colours of all ordinary stars, as constant features sensibly. Being 
observed, however, by the author, when he was on the peak of Teneriffe, 
in 1856, they were found nearly colourless, and without any diversity of 
tint, the one from the other. This observation appears to have been 
considered anomalous, and was so to a certain extent; but on examining 
older authorities the author has met with two other instances of an 
equality of pale colour being observed on the two components of 95 
Herculis—one by Sestini, in 1844-5, and the other by Struve in 1882-58 ; 
and remarks that while these two epochs are separated by twelve years 
exact to a tenth, the latter of them precedes the Teneriffe observation in 
1856-58 by almost exactly the same quantity. Now this looks like a 
regular periodic change, and in a very short period, for it is not impro- 
bable but that the twelve years is a multiple of a shorter period still, and 
during which the change of tint of the stars is so marked that from being 
merely grey at a certain time, one star has been described as becoming 
an ‘astonishing yellow green,’ and the other “an egregious red.” 
Although this is the first instance of this kind yet detected in the sky, 
the author thinks that it will not be found a solitary one; and that its 
phenomena may bear some relation to the ‘‘ eclipse” pink prominences of 
our sun, and to auroral displays about the earth. 
‘On a New Revolving Scale for Measuring Curved Lines.” By Mr 
H. Scunacintweit.—This instrument consisted of a small brass wheel re- 
volving in a short handle, the circumference about two inches round, 
having a number of very short steel pins inserted radially, the number 
depending on the scale to which it was desired to measure the curve ; and 
the side of the wheel having graduations corresponding to the pins on the 
circumference, the zero and other remarkable divisions being distinguished 
from the lesser graduations. 
‘¢On some Phenomena produced by the Refractive Power of the Eye.”’ 
By Mr A. Craupet.—This paper was to explain several effects of the re- 
fraction through the eye, one of which is, that objects situated a little be- 
hind us, are seen as if they were on a straight line from right to left. 
Another, that the pictures of external objects which are represented on 
the retina, are included in an angle much larger than one-half of the 
sphere at the centre of which the observer is placed; from this point of 
view a single glance encompasses a vast and splendid panorama extending 
to an angle of 200°. This is the result of the common law of refraction. 
Mr B.S. Procror read a paper ‘On the Focal Adjustment of the Hye.” 
M. Cuaupet exhibited his “ Star Chromatoscope,” a small telescope 
fixed upon a stand, and revolving. It is used to observe stars, and the 
effect produced is, that on looking through the instrument a luminous 
ring is seen reflecting the particular colour or colours of the star observed. 
Dr Ax read a paper “On the Transmutation of Spectral Rays,” 
including some curious speculations on the luminosity of the sun and stars. 
The Abbé Moreno exhibited and explained the “ Tenebroscope”’ in- 
vented by M. Soleil to illustrate the principle of the invisibility of light. 
The Abbé humorously observed that this term was somewat of an Irishism, 
but nevertheless it was a fact that light is quite invisible, for celestial space 
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