IMPROVEMENTS IN LAMP CASINGS OR HOLDERS FOR CONTAINING AND PROTECTING ELECTRIC LIGHTS, AND IN APPARATUS TO BE USED IN CONNECTION THEREWITH, THE SAID APPARATUS BEING IN PART APPLICABLE FOR OTHER PURPOSES
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by David Graham at the Office of the
Commissioners of Patents on the 14th July 1881.
DAVID GRAHAM, the younger, of Glasgow, in the County of Lanark, North
Britain. "IMPROVEMENTS IN LAMP CASINGS OR HOLDERS FOR CONTAINING AND
PROTECTING ELECTRIC LIGHTS, AND IN APPARATUS TO BE USED IN CONNECTION
THEREWITH, THE SAID APPARATUS BEING IN PART APPLICABLE FOR OTHER
PURPOSES."
The first part of this Invention relates to an improved casing or lanthorn for
containing and protecting electric lights, either the incandescent, partly incan-
descent, or arc lights. The lanthorn or casing when constructed for incandescent
lights consists of an upper part into which the conductors from a battery or an
electro-dynamic machine are led. This upper part is hollow in the inside, and so
arranged to receive the stem and contact pieces of a "Swan" or equivalent electric
lamp. This upper part is connected by one or more bayonet or equivalent joints
to the lower part or lanthorn proper, and are locked together by means of a
padlock, which consists of an upper and lower metallic portion connected together
by wires or bars of metal, bent or shaped according to the contour of the glass
portion of the lanthorn, this glass portion being preferably cushioned elastically
within the metallic portion and adjusted together with the protecting wires or
bars by a nut and screw, or equivalent arrangement, at the lower part. The upper
and lower parts of the lamp casing or lanthorn are provided with swivel rings for
suspending or carrying the same.
Lamps constructed as hereinbefore described are especially adapted for miners'
lamps and for subaqueous illumination.
In the case of using the lamp cases or lanthorns hereinbefore described for arc
lights, or partly are and partly incandescent lights, they must be made suffi-
ciently large to contain the mechanism used in connection with such lights.
The second part of the Invention relates to apparatus for making and breaking
contact, so that the spark produced at the making or breaking of contact is
prevented in the case of mines or other places where electric lights or other electric
apparatus is used from communicating with inflammable gases or other inflammable
material.

page_text: This apparatus consists of either a single or double receptacle which contains
mercury in the lower parts thereof in communication with the electric conductors.
Into this trough or troughs there dip metallic bars and the upper part of the
trough or troughs is filled with water or with water having oil floating, on it.
When therefore contact is made or broken by lowering or raising the bar or bars
into or out of the mercury, the spark then produced is by means of the water kept
from igniting any inflammable gases with which the atmosphere of the place where
such apparatus is used is or may be charged.
This last named apparatus may be used in any place or places wherein the
making and breaking of contact becomes necessary.
In another form of the apparatus for making and breaking contact, the use of a
metallic bar is dispensed with, and the apparatus in such case consists of one or
more vessels into or through which acidulated water or mercury capable of being
raised and lowered within a closed tube so as to make or break contact is
employed.