The sun is evidently going out of fashion, and is more and more
excluded from “good society” as our modern substitute for civilization
advances. “Serve him right!” many will say, for behaving so badly
during the last two summers. The old saw, which says something about
“early to bed and early to rise” is forgotten: we take “luncheon”
at dinner-time, dine at supper-time, make “morning” calls and go to
“morning” concerts, etc., late in the afternoon, say “Good morning”
until 6 or 7 P.M.; and thus, by sleeping through the bright hours of
the morning, and waking up fully only a little before sunset, the
demand for artificial light becomes almost overwhelming. Not only do we
require this during a longer period each day, but we insist upon more
and more, and still more yet, during that period.
The rushlight of our forefathers was superseded by an exotic
luxury, the big-flame candle made of Russian tallow, with a wick
of Transatlantic cotton. Presently this luxurious innovation was
superseded by the “mould candle;” the dip was consigned to the kitchen,
and the bloated aristocrats of the period indulged in a _pair_ of
candlesticks, alarming their grandmothers by the extravagance of
burning two candles on one table. Presently the mould candle was
snuffed out by the composite; then came the translucent pearly paraffin
candle, gas light, solar lamps, moderator lamps, and paraffin lamps.
Even these, with their brilliant white flame from a single wick, are
now insufficient, and we have duplex and even triplex wicks to satisfy
our demand for glaring mockeries of the departed sun.
Some are still living who remember the oil lamps in Cheapside and
Piccadilly, and the excitement caused by the brilliancy of the new gas
lamps; but now we are dissatisfied with these, and demand electric
lights for common thoroughfares, or some extravagant combination of
concentric or multiplex gas-jets to rival it.
The latest novelty is a device to render darkness visible by capturing
the sunbeams during the day, holding them as prisoners until after
sunset, and then setting them free in the night. The principle
is not a new discovery; the novelty lies in the application and
some improvements of detail. In the “Boy’s Own Book,” or “Endless
Amusement,” of thirty or forty years ago, are descriptions of “Canton’s
phosphorus,” or “solar phosphori,” and recipes for making them. Burnt
oyster-shells or oyster-shells burnt with sulphur, was one of these.
Various other methods of effecting combination between lime or baryta
with sulphur are described in old books, the result being the formation
of more or less of what modern chemists call calcium sulphide and
barium sulphide (or otherwise sulphide of calcium or sulphide of
barium). These compounds, when exposed to the sun, are mysteriously
acted upon by the solar rays, and put into such a condition that their
atoms or molecules, or whatever else constitutes their substance,
are set in motion—in that sort of motion which communicates to the
surrounding medium the wavy tremor which agitates our optic nerve and
produces the sensation of light.
Until lately, this property has served no other purpose than puzzling
philosophers, and amusing that class of boys who burn their fingers,
spoil their clothes, and make holes in their mothers’ table-covers,
with sulphuric acid, nitric acid, and other noxious chemicals. The
first idea of turning it to practical account was that of making a sort
of enamel of one or the other of these sulphides, and using it as a
coating for clock-faces. A surface thus coated and exposed to the light
during the day becomes faintly luminous at night.
Anybody desirous of seeing the sort of light which it emits, may do so
very easily by purchasing an unwashed smelt from the fishmonger, and
allowing it to dry with its natural slime upon it, then looking at it
in the dark. A sole or almost any other fish will answer the purpose,
but I name the smelt from having found it the most reliable in the
course of my own experiments. It emits a dull, ghostly light, with very
little penetrating power, which shows the shape of the fish, but casts
no perceptible light on objects around.
Thus the phosphorescent parish-clock face, with non-phosphorescent
figures and hands, would look like a pale ghost of the moon with dark
figures round it, and dark hands stretching across, by which the
time of the night might possibly be discovered there or thereabouts.
This invention has already appeared in a great many paragraphs, but,
hitherto, upon very few clock-faces.
Recently it has assumed a more ambitions form—patented, of course. The
patentees claim an improved phosphorescent powder, which is capable
of being worked up with the medium of paints and varnishes, and thus
applied, not merely to clock-faces, but to the whole of the walls and
ceilings of any apartment. In this case the faintness of the light will
be in some degree compensated by the extent of phosphorescent surface,
and it is just possible that the sum total of the light emitted from
walls and ceiling may be nearly equal to that of one mould candle. If
so, it will have some value as a means of lighting powder magazines
and places for storage of inflammable compounds. It is stated that one
of the London Dock companies is about to use it for its spirit vaults;
also that the Admiralty has already tried the paint at Whitehall, and
has ordered two compartments of the _Comus_ to be painted with it, in
order to test its capability of lighting the dark regions of ironclad
ships.
This application can, however, only be limited to those parts which
receive a fair amount of light during the day, for unless the
composition first receives light, it is not able afterwards to emit it,
and this emission or phosphorescence only continues a few hours after
the daylight has passed away; five or six hours is the time stated.
A theatrical manager is said to be negotiating for the exclusive right
to employ this weird illumination for scenic purposes. The sepulchre
scene in “Robert le Diable,” or the incantation in “Der Freischutz,” or
“The Sorcerer,” might be made especially effective by its ghostly aid.
The name-plates of streets, and buoys at sea might be advantageously
coated with such a composition; and many other uses suggest themselves.
There are rival inventors, as a matter of course. The French patentees
claim the use of cuttle-fish bones, various sea-shells, etc., mixed
with pure lime, sulphur, and calcined sea-salt, besides sulphides of
calcium, barium, strontium, uranium, magnesium, or aluminium. They
also add phosphorus itself, though for what purpose is questionable,
seeing that this substance is only luminous during the course of its
oxidation or slow combustion, and after this has ended the resultant
phosphoric acid is no more luminous than linseed oil or turpentine. An
admixture of phosphorus might temporarily increase the luminosity of a
_sample_, but any conclusions based upon this would be quite delusive.
They also assert that electrical discharges passed through the paint
increase its luminosity. According to some enthusiasts, electricity
is to do everything; but these ladies and gentlemen omit to calculate
the cost of rousing and feeding this omnipotent giant. In this case
electrical machinery for stimulating the paint for anything outside of
lecture-table experiments or theatrical and other sensational displays,
would be a commercial absurdity.
The Americans, of course, are re-inventing in this direction, but Mr.
Edison has not yet appeared on the luminous-paint scene. If he does we
shall doubtless hear of something very brilliant, even though we never
see it. In the meantime we may safely hope that this application of an
old scientific plaything to useful purposes may become of considerable
utility, as it evidently opens a wide field for further investigation
and progressive improvement, by the application of the enlarged powers
which modern science places at the disposal of ingenious inventors. We
hope, for the sake of all concerned, that it will not fall into the
hands of professional prospectus manufacturers and joint-stock-company
mongers, and that the story of its triumphs will be told without any
newspaper exaggerations.
Since the above was written—in February, 1880—I have tested
this luminous paint (Balmain’s patent). Practically, I find it
unsatisfactory. In the first place, its endurance is far shorter
than is stated. It begins to fade almost immediately the light is
withdrawn, and in the course of an hour or two it is, for all practical
use—though not absolutely—extinguished. Besides this it emits a very
unpleasant odor painfully resembling sewage and sulphureted hydrogen.
This is doubtless due to the sulphur compound, but is, I have no doubt,
quite harmless in spite of its suggestions.