mingling with the atmospheric air, introduced by a tube from the
outside, finally condenses as perfectly aërated fresh water in a
refrigerator, which is also in communication with the atmosphere. No
other means of agitation or percolation is so efficacious or
economical.' The apparatus, which is free from the defect of
depositing salt while distillation is going on, is rather more than
three feet in height, and eighteen inches diameter. It will yield two
pints of water per minute, at an expenditure of about 2-1/4 lbs. of
coal for each 45 lbs. of water.

Next, Monsieur Rochas proposes a method for preserving limestone
monuments and sculptures for an indefinite period. This material, as
is well known, is very liable to disintegrate, and the remedy is to
silicify it. Specimens of limestone so prepared were exhibited to the
Académie, but without any explanation of the process. We know that
brick and stone have been coated with glass in a few instances, to
insure their preservation; and that at Professor Owen's suggestion,
some decomposing ivory ornaments, sent over by Mr Layard, were
restored by boiling in gelatine; but M. Rochas aims at something still
greater--nothing less than the silicifying of a number of crumbling
limestone statues which have been lately discovered by a Frenchman who
is exploring the temple of Serapis at Memphis. They will then be
strong enough to bear removal.

Naturalists may learn something from Monsieur Falcony, who states that
a solution of sulphate of zinc is an effectual preservative of animals
or animal substances, intended for anatomical examination--it may be
used to inject veins, and the effects last a considerable time.
Another consideration is, that it is harmless: dissecting-instruments
left in the solution for twenty-four hours were not at all injured.