Improvements in Thermometers and Pyrometers.
Year: 1890

page_text: Date of Application, 20th Aug., 1890-Accepted, 15th Nov., 1890
COMPLETE SPECIFICATION.
Improvements in Thermometers and Pyrometers.
1, CARL JOSEPH CARIO, of Sudenburg near Magdeburg, in the Kingdom of Prussia,
German Empire, Engineer do hereby declare the nature of my said invention and in
what manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
It is a well-known matter, that bodies when exposed to heat are heated in proportion
to the temperature of the source of that heat; it is thus possible to utilize the rate of
expansion of a body under heat for determining the temperature of any source of heat
by measuring or indicating the rate of expansion, aforesaid.
The procedure forming the object of my invention depends on the principle
explained above, viz. on determining the temperature of any source of heat by
measuring the rate of expansion of a body subjected to that heat when conducted from
the source to any measuring instrument and by comparing the results obtained so with
known results of known degrees of temperature.
In order to make my invention more clear, I refer to the accompanying drawing,
which represents an arrangement depending on the principle of my invention and in
which similar letters denote similar parts.
The bulb a made of iron, porcelain or the like and provided with the tube b made
of the same material, is filled with quicksilver which when in normal condition, fills
the tube near to the line cd. The tube is provided with two electric contacts e
and f, one (e) slightly above the line cd, and the other (f) below the end of tube b. In
case the tube b be made of iron the electric contacts are insulated to prevent them
from being in metallic contact with the iron. Two binding-screws g and are
attached to the tube b, opposite the electric contacts, in order to connect tube with
the negative poles of the two batteries i and k, the positive poles of which are in
connection with one end of the coils of two electro-magnets and m.
The electro-magnets and m are placed in a box o, which contains a recording
apparatus p driven by any spring-motor not shewn by the drawing. Two rollers ?
and s are turned by said spring motor thus moving a band of paper laid around them.
The armatures of the electro-magnets are secured to double-armed levers and u,
provided with pencils and w, arranged so as to trace lines on the band of paper wben
pressed upon it.
e,
and
By connecting the other end of the electro-magnet / with the electric contact
the other end of the electro-magnet m with the electro-contact f two electric circuits
are formed working as follows:-
When heating the bulb a by any source of heat the quicksilver in the bulb a
begins to rise until it makes contact with the electric contact e, closing the
circuit n n' n².
The armature of the electro-magnet is attracted now thereby compelling the
pencil w to trace a line on the paper moved by the rollers and s with known speed.
The quicksilver extending further by the influence of the heat rises in the tube b
till coming in contact with the second electric contact f, closing thereby another
circuit. The armature of the electro-magnet m is attracted now thus compelling
the pencil v to trace another line on the band of paper, parallel to the first and
single line.
The length of the single line and the time necessary for tracing it serve to compute
the velocity of that heat the temperature of the source of which may be determined
now by the method explained above.
The tube o¹ drawn in dotted lines and enclosing the tabe b with the conducting wire
is intended firstly to protect the tube and the wire-connections and secondly to serve

page_text: measurements.
A number of arrangements different to that represented above may likewise be used
for measurements of such kind.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
The method of determining temperatures by measuring the rate of expansion of a
body, under such temperature, in combination with the means for ascertaining and
determining such rate of expansion and substantially as described.
Dated this 20th day of Araust 1800.
FREDK. WALKER,
11, Furnival Street, Holborn, London, E.C., Agent for the Applicant.