97 
SCIENTIFIC SUMMARY. 
ASTRONOMY. 
During the summer quarter the opportunities for planet and comet 
discoveries are rather limited on account of the shortness of the nights, so 
that there is but little to record for the last three months. A new variable 
star has been detected at the Madras Observatory by Mr. Pogson, which 
is, we believe, the only astronomical novelty of the season. 
Winnecke’s Comet . — The comet of short period known as Winnecke’s 
comes into sight in the winter of 1863, arriving at its shortest distance from 
the sun on November 23. It w T ill not be well seen in those latitudes on 
this occasion. It sets about an hour after the sun during the month of 
November, and from one to two hours in that of December ; and being in 
the same parallel, it w T ill of course be faint from the strong twilight in 
that quarter. In the months of January and February it will be a little 
more favourably situated, but its distance from the sun and earth will 
have increased considerably. It is situated in the constellation of Libra 
at the beginning of November, and passes to Capricornus at the end of the 
year. On Nov. 2, its R.A. is 15 h 9 m ; Nov. 18, 16 h 34 m ; Nov. 30, 
I7 h 45 m ; Dec. 12, 18 h 59 m ; and Dec. 28, 20 h 33 m . Its south declinations 
at those times respectively are 13° 23', 19° 44', 23° 4', 24° 24', and 
22° 53'. This will serve to indicate its path to those who may turn their 
telescopes in that direction. It is at its shortest distance from the earth 
on Dec. 8, when it will be more than 150 millions of miles distant. Its 
shortest distance from the sun is 73 millions of miles. 
* Distance of Sun from the Earth . — Professor Hansen has deduced from 
his lunar tables a value of the solar parallax, closely agreeing with that 
given by the late opposition of Mars as discussed by Mr. Stone. Mr. 
Hind has drawn up a long and valuable account of the later history of 
this important question, which it is to be hoped will be set at rest in less 
than twenty years’ time — it cannot be done sooner in all probability. 
The increase of the solar parallax from 8"*5776 to 8"*95 depends on 
six entirely distinct authorities, but astronomers will probably retain the 
old value until the next transit of Venus. It may be remarked, en passant, 
that the value found from the passage of Venus in 1769, taking the 
observations made at Otalieite, California, Hudson’s Bay, and combining 
them with those of Paris and Petersburg, gives a parallax of 8"*9142, 
very nearly the same as that lately suspected. The extreme results 
given by the observations on that occasion are very different, being 
8"*15 and 9"’25. Doubtless on the next occasion those great discrepancies 
will not occur, as we may fairly expect more experienced observers and 
YOL. III. — NO. IX. H 
