548 
SCIENTIFIC SUMMARY. 
QUARTERLY RETROSPECT. 
ASTRONOMY. 
Solar and Lunar Eclipses . — A partial solar and total lunar eclipse — the 
former on the evening of May 17, and the latter on the night of June 1 — 
have been favourably observed throughout the British Islands generally. 
The small portion of the solar surface eclipsed in the first (only 03 at 
London) produced little if any darkness or other phenomena, and observers 
could only notice the passage of the moon’s disc over some of the spots, 
and the roughness of the moon’s edges when projected on very strong 
light. The lunar eclipse was more interesting, and the gradual extinction 
of the moon’s white light by umbra and penumbra, until only a dusky red 
patch was left in the sky, was more remarkable than any seen of late years. 
In some total eclipses of the moon it has been noticed that its surface is 
much brighter than on other occasions, and this has been held to be due to 
the distance of the moon from the earth at the time ; i. e., if the moon be 
at its shortest distance, the shadow (being larger) will more completely en- 
velope the moon, and the latter be in consequence darker, and vice versa. 
The moon was very near its perigee on the present occasion, so that the very 
considerable darkness observed may be taken as a further proof of this 
very natural explanation. The colour of the shadow on the moon was 
variable as the eclipse proceeded, being at first of an inky or greyish tint ; 
but as the time of total eclipse approached, the hidden portion became 
gradually redder, the penumbra assuming a bluish colour, which is ex- 
plained by the contrast between the red and light silvery part of the moon’s 
disc; and the same effect was noticed as the shadow disappeared from the 
moon. The white spots on the floor of the mountain Plato were even con- 
spicuous as the penumbra passed over that part. Another total eclipse of 
the moon will not be visible in England for some years, and it is but seldom 
that one is observed under such favourable circumstances. 
Spectra of Stars . — Since Donati’s memoir on this subject, published in 
the course of last year, it has engaged the attention of numerous observers; 
but the variety of detail seen by Secchi at the Roman Observatory (being 
probably favoured with a fine atmosphere at the time) is very remarkable, 
although, as yet, his determinations of the lines of only five stars have been 
published. Mr. Huggins and Dr. Miller have made a more extensive 
series on thirty or forty stars, and have been able to obtain microscopic pho- 
tographs of Sirius and Capella. An ingenious method has been devised by 
