n taken with the theatre of the Port St.
Martin, at Paris. A thick wall of hewn stone separates the audience part
from the scenic part of the house; all the doors in it are of iron, and
may be shut instantly, in case of fire; finally, the insulation of the
spectators from the stage is made perfect by means of a screen of plates
of iron, which falls down before the stage. This screen, which weighs
between 1,200 and 1,300 pounds, is easily worked by two men, and slides
up and down upon guides, so as readily to take its place. Besides these
precautions, reservoirs of water are established in the roof, which may
be connected, when necessary, with vessels of compressed air, and made to
throw a powerful jet over a very large part of the building.--_French
Paper_.

_Tanning_.

A tanner, named Rapedius, of Bern Castel, on the Moselle, has discovered
a new species of tan proper for dressing leather. It is the plant known
by the name of Bilberry or Whortleberry, (Vaccinium Myrtilus or
Myrtillis,) which should be gathered in spring, because at this season it
dries more readily, and is more easily ground. Three pounds and a half of
this tan suffice for dressing a pound of leather, while six pounds are
required from the oak to produce the same effect. By this new process,
tanners can gain four months out of the time required for preparing
strong leather. A commission having been appointed at Treves to examine
the leather so prepared, reported, that they had never seen any as good,
and that every pair of shoes made therefrom lasts two months more than
what are manufactured from common leather; that the skin of the neck,
which it is difficult to work, becomes strong and elastic like that of
the other parts. The shrub should not be pulled up, but cut with a bill,
to obtain the reproduction of the plant the following year. When cut,
damp does not deteriorate it, which is not the case with oak bark, which
loses ten per cent. of its value by being wetted.--_From the French_.

_Spiders_.

It would be very interesting to know whether the gossamer threads thrown
out by these insects are in an excited state of electricity: their
divergent state would seem to imply they were; for there seems to be no
other natural cause which could prevent them from coming together,
especially before the insect had left its resting-place. If electric,
then neighbouring bodies, as the hand or branches of a tree, or a stick,
&c., would attract them; but