Year: 1860




The following clear statement of most
important discovery which has recently been
made by NJ. Gassiot in the production of
light by electricity we take from the Lon
don Photographic News'


A most interesting application of some
very elaborate and abstruse researches in
physical optics has recently been made by
NJ. GassiOt. IL has long been desideratum
to obtain o source of light without heat. Ir-
respective of the great advantages of such a
discovery to the photographer, its value
would be almost inestimable in many other
branches of science. The surgeon, for in
stance, has hitherto been compelled to per-
form many operations-upon which the
health, perhaps the life, of his patient de-
pends-almost in the dark; while the saving
Of life which would necessarily follow the
introduction of such a safe means of illu-
mination in our coal mines, would be incalcu-
liable. M. Gassiot has we fancy, at last sue
ceeded in solving the problem, and that by
an application of some of the most recon-
dite and, to the mere utilitarian, apparently
useless, investigations ever commenced by
scientific man. 1t has long been known that
under certain circumstances, the electric dis
charge from voltaio battery can be made
to traverse short distances across air in the
form of an intensely luminous, but at the
same time, intensely hot spark. If this dis
charge is made to pass through glass tube
by means of platieum wires sealed into the
extremities--the air having previously been
exhausted from it by means Of an air-pump-
the discharge assumes an entirely different
aspect.


Instead of appearing in the form of dis
connected sparks, the electric fluid traverses
it like a continuous stream of nebulous
1inrl,t E11inrr fha ,hn IL
phorescent glow, while the heat almost dis
appears; on this account it was until very
recently considered that q vacuum con-
Quoted electricity. Recent researches have,
however, shown that vacuum really is a
non-conductor to the passage of this electric
fluid; and that the phenomenon of con-
duction apparent in the vacuum tube, was
really due to the great conducting power
possessed by highly rarifed gas. AS soon
as this was known, it became a matter of
great interest to philosophers TO ascertain
the various effects which would be produced
by having the tube filed with different sorts
of gases, and also what difference was
caused by alterations in the size or shape OF
the vacuum tubes employed.


Among these experimeRtalists, NJ. Gassiot
occupied one of the first positions; and as
an adaptation of some of his researches to
the wants Of everyday life, he has given to
Tie WOTtu u Feduy anu simple means OF aD-
plying the electric discharge from the in
dustion coil to The purposes of illumination.
A carbonic and vacuum tube, (that is, a tube
filled with carbonfc acid, which is then ex-
bausted from it by means of an air-pump,
until there is only the most infinitessimai
trace of gas remaining having an internal
diameter of about one-siXteenth of an inch,
is wound in the form of fattened SPIRAL to
the ends of the tubes are attached two
wider tubes, into which platinum wires are
sealed; they are inclosed in wooden case,
so as to permit only the spiral to be exposed.


When discharge from a Ruhmkorff7s in
duction apparatus is passed through the
vacuum tube, the spiral becomes intensely
luminous, exhibiting brilliant white light.
NJ. .Gassiot, who exhibited the instrument In
action at a recent meeting of the Royal So
ciety, caused the discharge to be passed
through two miles of copper wire, showing
that il would be applicable to illumination
at distance. The results were brilliant in
the extreme, and we confidently predict that
this beautiful contribution of abstract science
to every day life will very shortly be one of
the most useful and popular forms of the
electric light.