le than in the animal creation, and the great extent of surface
of the foliage of plants is admirably calculated for carrying it on in
sufficient quantities. This transpired fluid consists of little more
than water. The sap, by this process, is converted into a liquid of
greater consistence, which is fit to be assimilated to its several
parts.

EMILY.

Vegetation, then, must be essentially injured by destroying the leaves
of the plant?

MRS. B.

Undoubtedly; it not only diminishes the transpiration, but also the
absorption by the roots; for the quantity of sap absorbed is always in
proportion to the quantity of fluid thrown off by transpiration. You
see, therefore, the necessity that a young plant should unfold its
leaves as soon as it begins to derive its nourishment from the soil;
and, accordingly, you will find that those lupines which have dropped
their seed-leaves, and are no longer fed by the parenchyma, have spread
their foliage, in order to perform the office just described.

But I should inform you that this function of transpiration seems to be
confined to the upper surface of the leaves, whilst, on the contrary,
the lower surface, which is more rough and uneven, and furnished with a
kind of hair or down, is destined to absorb moisture, or such other
ingredients as the plant derives from the atmosphere.

As soon as a young plant makes its appearance above ground, light, as
well as air, becomes necessary to its preservation. Light is essential
to the development of the colours, and to the thriving of the plant. You
may have often observed what a predilection vegetables have for the
light. If you make any plants grow in a room, they all spread their
leaves, and extend their branches towards the windows.

CAROLINE.

And many plants close up their flowers as soon as it is dark.

EMILY.

But may not this be owing to the cold and dampness of the evening air?

MRS. B.

That does not appear to be the case; for in a course of curious
experiments, made by Mr. Senebier, of Geneva, on plants which he reared
by lamp-light, he found that the flowers closed their petals whenever
the lamps were extinguished.

EMILY.

But pray, why is air essential to vegetation, plants do not breathe it
like animals?

MRS. B.

At least not in the same manner; but they certainly derive some
principles from the atmosphere, and yield others to it. Indeed, it is
chiefly owing to the action of the atmosphere and the vegetabl