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POPULAR SCIENCE REVIEW. 
posing that a certain amount of dialytic action occurs in certain thin metallic 
septa, enabling them to separate hydrogen from other gases. 
The Spectrum of Aqueous Vapour. — M. Jannsen records some very interest- 
ing experiments on the spectra of steam. In his experiments he employed an 
iron tube thirty-seven metres long filled with steam, of a pressure of seven 
atmospheres. The light was obtained from sixteen gas-jets. The spectrum 
showed five dark bands, of which two well marked answered to D and A 
(Fraunhofer), and reminded the observer of the solar spectrum seen in the 
same instrument towards sun-set. According to the first comparisons made 
between the spectrum of steam and that of solar light it appeared that the 
group A of Fraunhofer, B (in great part at least), the group C, two groups 
between C and D, are due to the aqueous vapour in the atmosphere. The 
experiment gave another interesting result. The spectrum was very dark at 
the violet end, and brilliant in the red and yellow, showing that aqueous 
vapour is very transparent to the latter rays, and suggesting that it will 
appear orange-red by transmission, and redder according to the thickness of 
the layer. This result, the author states, requires to be verified with care, 
but if established, he says, it will explain the redness always observed at 
sunrise and sunset. M. Jannsen hopes soon to be in a position to pronounce 
upon the existence or non-existence of aqueous vapour in the atmospheres of 
the planets and other stars. At present he is only able to say that it is not 
present in the atmosphere of the sun. — Vide Comptes Bendus, August 13th. 
Meteoric Stones. — M. Daubree records his observations on a great shower 
of meteoric stones which fell on the 30th of May, in the territory of Saint 
Mesmin, in the Department of the Aube. M. Daubree gives the following 
account of the phenomenon : — The weather being fine and dry, and only a 
few clouds in the sky, at about 4.45 in the morning a luminous mass was seen 
to cross the sky with great rapidity, and shedding a great light between Mes- 
grigny and Payns. A few seconds after this appearance, three loud explo- 
sions like the report of cannon were heard at intervals of one or two seconds. 
Several minor explosions, like those of muskets, followed the first, and suc- 
ceeded one another like the discharge of skirmishers. After the detonations 
a tongue of fire darted towards the earth, and at the same time a hissing noise 
was heard like that of a squib, but much louder. This again was followed by 
a dull, heavy sound, which a person compared to that of a shell striking the 
earth near him. After a long search he perceived, at the distance of about 
two hundred feet from the place where he was when he heard the noise, a 
spot where the earth had been newly disturbed ; he examined the place, and 
saw a black stone at the bottom of a hole nine inches deep, which it seemed to 
have formed. This stone weighs nearly ten pounds. On the following day 
a gendarme named Framonnot picked up another meteoric stone of the same 
nature, weighing nearly seven pounds, at about two thousand feet distant 
from where the first fell. A third stone was found on the 1st of June by a 
man named Prosat, five to six thousand feet from the two spots above referred 
to. This last meteorite weighs nearly four pounds and a half. 
The Atlantic Cable. — The French savants do not seem to believe much in 
the Atlantic Cable as a commercial success, but they think it may be put to 
great and valuable scientific purposes. At a recent meeting of the French 
Academy M. Babinet, after expressing doubts as to the success of the cable, 
