A Catechism of Familiar Things | Page 3

use is this power to vegetables?
The water which they decompose affords them nourishment for the
support of their vital juices, and enables them, by combining the fluid
gases which compose it with those of the air and the soil, to form their
different products; while the superfluous gas is abundantly given out by
their leaves, to refresh the spent air, and render it wholesome for the
animals that breathe it.

Vital, belonging to life, necessary to existence.
Superfluous, unnecessary, not wanted.
What is Rain?
The condensed aqueous vapors raised in the atmosphere by the sun and
wind, converted into clouds, which fall in rain, snow, hail, or mist: their
falling is occasioned by their own weight in a collision produced by
contrary currents of wind, from the clouds passing into a colder part of
the air, or by electricity. If the vapors are more copious, and rise a little
higher, they form a mist or fog, which is visible to the eye; higher still
they produce rain. Hence we may account for the changes of the
weather: why a cold summer is always a wet one--a warm, a dry one.
Aqueous, watery; consisting of water.
Collision, a striking together, a clash, a meeting.
Electricity, a natural agent existing in all bodies (see page 18).
What seasons are more liable to rain than others?
The Spring and Autumn are generally the most rainy seasons, the
vapors rise more plentifully in Spring; and in the Autumn, as the sun
recedes from us and the cold increases, the vapors, which lingered
above us during the summer heats, fall more easily.
Recede, to fall back, to retreat.
What is Snow?
Rain congealed by cold in the atmosphere, which causes it to fall to the
earth in white flakes. Snow fertilizes the ground by defending the roots
of plants from the intenser cold of the air and the piercing winds.
Congealed, turned by the force of cold from a fluid to a solid state;
hardened.

Fertilize, to render fruitful.
Intenser, raised to a higher degree, more powerful.
What is Hail?
Drops of rain frozen in their passage through cold air. Hail assumes
various figures according to the degrees of heat or cold through which
it passes, being sometimes round, flat, &c.
What is the Atmosphere?
The mass of aëriform fluid which encompasses the earth on all sides: it
extends about fifty miles above its surface. Air is the elastic fluid of
which it is composed.
Elastic, having the power of springing back, or recovering its former
figure after the removal of any external pressure which has altered that
figure. When the force which compresses the air is removed, it expands
and resumes its former state.
What are the uses of air?
It is necessary to the well-being of man, since without it neither he nor
any animal or vegetable could exist. If it were not for atmospheric air,
we should be unable to converse with each other; we should know
nothing of sound or smell; or of the pleasures which arise from the
variegated prospects which surround us: it is to the presence of air and
carbonic acid that water owes its agreeable taste. Boiling deprives it of
the greater part of these, and renders it insipid.
Variegated, diversified, changed; adorned with different colors.
Insipid, tasteless.
What is Wind?
Air in motion with any degree of velocity.

What is Lightning?
The effect of electricity in the clouds. A flash of lightning is simply a
stream of the electric fluid passing from the clouds to the earth, from
the earth to the clouds, or from one cloud to another. Lightning usually
strikes the highest and most pointed objects, as high hills, trees, spires,
masts of ships, &c.
What is Thunder?
The report which accompanies the electrical union of the clouds: or the
echoes of the report between them and the earth. Thunder is caused by
a sudden discharge of electrical matter collected in the air, by which
vibrations are produced, which give rise to the sound.
What is Electricity?
One of those agents passing through the earth and all substances,
without giving any outward signs of its presence, when at rest; yet
when active, often producing violent and destructive effects. It is
supposed to be a highly elastic fluid, capable of moving through matter.
Clouds owe their form and existence, probably, to it; and it passes
through all substances, but more easily through metals, water, the
human body, &c., which are called conductors, than through air, glass,
and silk, which are called _non_-conductors. When bodies are not
surrounded with non-conductors, the electricity escapes quickly into
the earth.
To what part of bodies is Electricity confined?
To their surfaces, as the outside may be electric, and the inside in a
state of neutrality. The heat produced by an electric