1868. | Physics. 261 
blue tints generally seen during the occurrence of this phenomenon, 
while other observers had noticed these tints distinctly. The paper 
alluded to is an explanation of the discrepancy. Mr. A. Brothers 
had previously, at a meeting of the Manchester Literary and 
Philosophical Society, read a paper, in the course of which he com- 
pared the statements of different observers. He had himself dis- 
tinctly seen colour, with a refractor of five inches aperture. The 
moon’s surface presented, owing to the presence of this colour, an 
appearance of great beauty, which seemed to increase as the pen- 
umbral shadow stole over it. The colour of the eclipsed limb was 
of a coppery hue, much brighter towards the part most deeply 
within the shadow. The part of the moon not eclipsed was of a 
beautiful bluish-grey colour. Mr. Browning’s evidence, published 
in the ‘ Astronomical Register,’ was—“ I looked most carefully for 
colour, both with the 104-inch silvered-glass reflector, furnished 
with an achromatic eye-piece of very low power, and also with a 
five-feet refractor; with neither could I detect a trace.” Mr. 
Slack observing in the same locality, with a silvered-glass reflector, 
writes in the ‘ Intellectual Observer ’—*“ After twelve the eclipsed 
limb grew noticeably redder, the red coppery tint chiefly affected 
the lower parts of the obscured limb, but was visible further in, 
gradually blending with the inky tints presented by the umbra at 
its advancing edge.” Lastly, Mr. Weston, who was observing at 
Lansdown, near Bath, saw colour. He recorded the following in the 
‘Monthly Notices’ :—“ The prevailing colours were red-bluish and 
grey, and grey: the redness increased towards the darkened edge 
of the moon.” Mr. Brothers thinks that the appearance of colour 
cannot be caused by the telescope or by peculiarities in the eyes of 
the observers, proved by the fact that the same colours are seen, 
whether refractors or reflectors, either of metal or silvered glass, be 
used; and as the majority of observers of the phenomenon see 
colour, he thinks the eyes of those who remark its absence are 
perhaps afflicted with colour blindness. 
Mr. Browning, in the paper first alluded to, says that his 
having used a telescope of larger diameter than that possessed by 
the telescopes employed by most of the other observers had been 
suggested as a probable explanation by Mr. Slack, as well as by 
Mr. Huggins. The result of inquiries he has instituted completely 
confirms the idea. He finds that while most observers who 
used telescopes of only three or four inches aperture speak of the 
colour as being less than usual yet very noticeable, observers who 
used telescopes of seven or eight inches aperture saw very little 
colour. Three other observers using telescopes with large apertures 
failed to detect any colour. Experimenting in connection with this 
subject, he has noticed that the chocolate colour of the so-called 
