|The Secret of Everyday Things|
|by Jean Henri Fabre|
|Fascinating conversations with Uncle Paul reveal the mysteries behind the dyeing and weaving of cloth, the lighting and heating of homes, the processing involved in bringing oil, coffee, tea, spices, and other foodstuffs to the table, and the power of water in all its manifestations. Excellent as follow-on to The Story Book of Science. Ages 11-14 |
HE crudest method of lighting that I have ever seen is
to be found in certain out-of-the-way corners of our
mountain districts. Under the mantel of an immense
fireplace there stands, on one side, a box of salt,
kept dry by the heat of the fire, while on the other
projects a large flat stone on which in the evening,
with true economy, resinous splinters from the trunk of
a fir-tree are burnt; and that is the only light, the
only lamp, in the dwelling. By the light of this red
and smoky flame the housewife prepares the soup and
pours it into the porringers for the family returned
from their labor in the fields, while the grandmother,
silent in her big arm-chair, plies the spindle with her
"A common oil-lamp," said Claire, "would be far
preferable to that little fire of resinous wood."
"I do not deny it," replied Uncle Paul; "but oil costs
money, and a few little splinters of fir cost nothing."
"But that pitch-pine torch only gives light right round
the fireplace. For going at night from one room to the
next some other kind of light is needed."
"They have the iron lamp, in which a cotton wick
inserted in a sort of socket burns grudgingly a few
drops of nut oil."
 "That must give a very poor light—not so good as a
candle, even the kind that makes such a horrid smell."
"What are those bad-smelling candles made of, Uncle
Paul?" asked Emile.
"They are made of either mutton or beef fat, which we
know by the name of the tallow."
"There are others, of a beautiful white, that are not
greasy to the touch and have hardly any smell."
"Those are tapers, or wax-candles, as they are called,
and they are far superior to common candles, although
made from the same material, tallow. It is true that
the tallow destined for tapers undergoes thorough
purification, which removes its disagreeable odor and
its oil. The first step in this process is the boiling
of the tallow in water to which lime has been added.
Next there is called into service a powerful drug, oil
of vitriol, which takes away the lime as soon as it has
acted sufficiently. Finally the material under
treatment is subjected to strong pressure which
squeezes out and gets rid of the oily ingredient. After
passing through these various stages the tallow is no
longer what it was. It has no smell, or hardly any; its
consistency is firm, its color a perfect white. In this
new state, which is very different from the first, it
is no longer called tallow but stearin.
"The notable improvement I have just described, which
was destined to give us the odorless taper with its
white flame in place of the foul-smelling, smoky
tallow-candle, dates from the year 1831.
"Tapers, or wax-candles, are made in molds, which
 are of metal and open at their base into a common
reservoir the use of which I will explain presently.
Through each mold, running from end to end, passes a
wick, which is fastened at the bottom by a small wooden
pin, and at the top by a knot that rests on the little
central opening of a conical cap. After the molds have
been placed in position, with their pointed ends
downward and their bases upward, the melted stearin is
poured into the reservoir, whence it runs into the
several molds. Nothing more remains to be done except
to bleach and polish the candles. They are bleached by
exposure to the sunlight for some time, and polished by
rubbing with a piece of cloth.
"Oil, which I will speak of in detail later, is also
used for lighting. There are several inferior kinds
commanding so low a price as to permit of their use.
Those in most common demand for lighting are rape-seed
oil, colza oil, and nut oil. They are burned by the use
of a woven cotton wick which soaks up the liquid at its
lower end and brings it drop by drop to the flame.
"If the candle is allowed to burn fully exposed to the
air, with no protecting glass chimney to regulate and
increase the draft, the flame is dim and smoky, a part
of the oil, decomposed by the heat, being lost in smoke
or collecting in the form of snuff on the incandescent
part of the wick. To burn this smoke, this carbon, and
thus obtain a brighter light, a good draft must be
generated, as in fireplaces and stoves, so as to
utilize to the full the fuel that feeds the flame. This
is attained by means of a glass chimney
 enclosing and surrounding the flame, allowing cold air
to enter at the bottom and hot air to escape at the
top. Only on this condition do lamps, of whatever sort,
give a good light."
"I thought," said Marie, "that lamp-chimneys were only
to protect the flame from puffs of air."
"Chimneys do indeed protect the flame from puffs of air
that might make it flicker and go out, but they also
fill another office no less useful: they generate a
draft without which combustion would be imperfect and
the light dim. If you remove the chimney you will
notice that the flame immediately becomes smoky and
dim; put the chimney on again, and the flame will
instantly recover its vigor and clearness. It is the
same with the lamp as with the stove: without a
sufficiently long pipe to create a draft, or, in other
words, to draw in air to the very heart of the fuel,
the stove would burn badly and give out little heat;
and without the glass chimney bringing to the wick a
continual stream of fresh air the lamp would make but
poor use of its oil supply and would give only a faint
"The chimney is especially indispensable with lamps
that burn kerosene, a liquid very much used at the
present time for lighting. The lamp hanging from the
ceiling of this room to give us light in the evening is
filled with kerosene. You must have noticed the great
difference it makes with the lighted wick whether the
chimney is on or off."
"That difference has always struck me," Marie replied.
"Before the chimney is on the flame is red, very smoky,
and gives hardly any light; but as soon
 as the chimney is put on, the smoke disappears and the
flame turns a very bright white. Without its chimney
the lamp would not give much light and would fill the
room with black smoke."
"In kerosene lamps the air necessary for combustion
comes through a number of little holes in the metal
disk that supports the chimney. If these holes become
obstructed with the carbonized refuse of the wick, the
draft works badly and the lamp smokes. Then sometimes,
ignorant of this detail, you are lost in conjecture as
to the cause of the wretched light you are getting. The
wick is badly trimmed, you say to yourself, it is too
long or too short, there is not enough oil, or there is
too much. You try this and that remedy, all to no
purpose; the lamp still smokes. The right remedy is
nevertheless very simple: it is only to take off the
metal disk through which the wick runs, and with a
brush thoroughly to clean the little holes with which
it is riddled. These openings clean, the air once more
comes freely to the flame, a draft is created without
any obstacle, and the lamp burns as brightly as ever."
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