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POPULAR SCIENCE REVIEW. 
distance from tlie sun was 44 millions of miles, and their 
motion was direct. These quantities, which determine the 
path of the comet round the sun, are altogether discordant 
with those given by the wanderer of June, 1861. According 
to my calculations, which agree with those of others, the lon- 
gitude of the ascending node of the latter was 278° 59'; that 
of perihelion, 249° 15'. The inclination of the orbit to the 
ecliptic was 85° 39'; whilst its least distance from the sun 
was 78 millions of miles. The motion was direct. It mil 
be seen from this, that we must yet be on the look-out for 
the comet of 1556, in case it has not already passed away 
unnoticed, a supposition which is becoming more and more 
probable every day. 
Although, however, we were not fortunate enough to witness 
the reappearance of those celebrated historical comets, yet there 
were other circumstances connected with the present object 
which were scarcely less marvellous. From the calculations of 
Professor Hind, it would seem possible that the earth passed 
through the tail of the comet on the afternoon of June 30th, 
and an unusual glare in the sky was noticed by himself and 
several others on that evening, which was attributed at the 
time to an auroral light. When it is remembered (according to 
the calculations of the astronomer Olbers) that the probability 
of the earth coming* into collision with the atmosphere of a 
comet could only occur once in 8 or 9 millions of years (the 
probability of the earth coming into collision with the nucleus 
of a comet, he calculates could only occur once in 220 millions 
of years), we may conclude, within fair limits, that nothing 
of this kind has occurred since the creation of man. Had 
such an event been prognosticated, the terror which would 
have ensued may be easily imagined ; nor would it have been 
altogether dissipated even if we took the more favourable 
views of the astronomer Pape, who computes that the distance 
of the tail of the comet from the earth was at least 2} millions 
of miles on this occasion. We once heard St. Marc Gfirardin 
repeat a mot of M. Babinet, who asserted that the shock which 
the earth would receive from collision with a comet would be 
no greater than that received by a locomotive in full speed 
meeting with a fly. But the fly in this instance might cause as 
much alarm as the spider in another, of which the poet says — 
“ There may be in the cup 
A spider steeped, and one may drink ; depart, 
And yet partake no venom ; for his knowledge 
Is not infected ; but if one present 
The abhorred ingredient to his eye” — 
the case would be different, especially when the poisoned 
atmosphere of a comet might be expected to mingle with and 
