AN IMPROVED METHOD OF AND APPARATUS FOR EFFECTING THE ILLUMINATION OF COMPASS CARDS, CLOCK DIALS, AND STEAM and Water GauGES, AND FOR OTHER LIKE PURPOSES
Year: 1874

page_text: :
PROVISIONAL SPECIFICATION left by George Haseltine at the Office
of the Commissioners of Patents, with his Petition, on the 5th
August 1874.-A communication from abroad by Henry Oceanus
Cook, of Brooklyn, New York, United States of America.
I, GEORGE HASELTINE, of the "International Patent Office," South-
ampton Buildings, London, Doctor of Laws, do hereby declare the
nature of the said Invention for "AN IMPROVED METHOD OF AND APPARATUS
FOR EFFECTING THE ILLUMINATION OF COMPASS CARDS, CLOCK DIALS, AND STEAM
and Water GauGES, AND FOR OTHER LIKE PURPOSES," a communication, to bo
as follows:-
When the electric force is transmitted through an attenuated gaseous
medium, between the terminal points of a metallic conductor, tho
intensity of the flash is diminished and is changed to a luminous glow
or diffusion of light, the color of which is characteristic with different
gases.
The extent of the interval through which the diffusion may bo
effected is also increased by the attenuation, so that the flash or spark,
which will fail to pass over the space of an inch between the terminals

page_text: in an atmosphere of the ordinary density, may be extended over several
feet through the same medium when enclosed and rarefied by connection
with a partial vacuum.
The object of my Invention is to apply the luminous effect of the
transmission of electricity through rarefied gases to the illumination of
compass cards, clock dials, and steam and water gauges, and to other
similar purposes for which an intense or brilliant light may not be
necessary. To accomplish this purpose the said Invention consists in
combining with the object to be illuminated a transparent tube that
has been partially exhausted, and in the opposite ends of which are
hermetically sealed the ends of the metallic conductors from an induction
coil and battery.
A convenient method of illuminating a compass consists in making
the card of mica or other translucent material upon which the points
have been marked, and in suspending below it the electric tube in the
form of a ring through the attenuated gas, in which may be transmitted
the electric force or the discontinuous current of electricity that pro-
duces the illumination. A Ruhmkorf's coil and a sulphate of mercury
battery or other means for the generation of electricity may be com-
bined and enclosed within the case. In this manner the compass may
be observed under a mild radianco that is sufficient for the purpose, and
is much preferable to the glare of light proceeding from ignition or
combustion that unfits momentarily, at least, the eye from effectually
performing its duty in looking out upon the sea and sky in the darkness
of the night.
In a glass water gauge attached to a steam boiler for the purpose of
exhibiting the level of the water, the electric tube may be a similar
tube placed between the water tube and the boiler, so that the luminous
glow may be transmitted through the exterior water and steam.
The electric tube may also be bent so as to extend on each side of tho
tubo to bo illuminated, and it may be furnished with internal tubes or
vessels with appropriate contents for the purpose of developing a fluo-
rescent and persistent light.