has been soaked in the lime water. A great variety
of substances have been used for tanning, as the acorn-cup of the
oriental bark; catechu and sumach have been also used; but the oak bark
is most generally used, as furnishing a large quantity of astringent
matter. It is not the business of the chemist to describe the different
kinds of leather, but I may just mention, that the upper leather of
shoes is called _curried_ leather; the leather having been tanned, is
rubbed over with oil before it is dried, and it is then very flexible,
pliable, and durable; but if you take a piece of dry leather, and try to
rub it over with oil or grease, you cannot make it enter the pores of
the leather; the black colour is produced by rubbing it over with a
solution of green vitriol, the sulphate of iron. _Russian_ leather is
tanned in an infusion of birch bark, and is said to be afterwards mixed
with a quantity of birch tar, to give it that odour for which it is
peculiar, which renders it valuable for book-binding, on account of
preventing it from being attacked by insects. _Tawed_ leather, used for
gloves, is made by impregnating the skin with a liquor containing alum
and salt, and afterwards washed in a mixture of yolks of eggs and water;
the saline and animal matters combine, and give it that peculiar
softness, and such leather is afterwards coloured as may be required;
having been rolled over wooden rollers, in which are grooves, it is
called _Morocco_ leather. These are the principal varieties of leather
employed in this country.--_Brande's Lectures--Lancet_.

_Mites_.

An indefatigable naturalist has undertaken the very difficult task
of arranging the family of _acarides_, or mites; he divides them into
sixty-nine genera, the greater part of them new!

_Electro-Attraction of Leaves_.

The results of a French experimentalist have lately led him to conclude
that the leaves, hairs, and thorns of plants tend to maintain in them
the requisite proportion of electricity; and, by drawing off from the
atmosphere what is superabundant, they also act in some measure as
thunder-rods.

_Enormous Whale_.

The skeleton of a whale, 95 feet long by 18 feet high, has lately been
deposited in the Cabinet of Natural History at Ghent. In the opinion of
many naturalists, among whom is M. Cuvier, this fish could not have been
less than 900 or 1,000 years old!

_Fly in Wheat_.

In North America, much damage is done to crops of wheat by