Improvements in Thermometers.
Year: 1895

page_text: Date of Application, 7th May, 1895-Accepted, 3rd Aug., 1895
COMPLETE SPECIFICATION.
Improvements in Thermometers.
I, ROBERT MULLER, of 59 Grabenstrasse, Essen, a/K in the Empire of
Germany, Glass Blower, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention relates to a double thermometer whereby simultaneous or parallel
experiments on the temperature of gases, liquids ele, may be effected in a highly
sensitive manner.
The apparatus consists of two single equal thermometers which are based on
the principle of an air thermometer.
The essential fenture in the arrangement is the application of a removable air
capsule which is connected with a graduated U shaped tube by means of an india
rubber tube
The mercury thermometers usually employed for experimental pm poses have the
disadvantage that the reflection of the mercury endors the reading off, from a
certain distance difficult.
The air thermometers hitherto used are also not very convenient and their use 18.
limited
In carrying out my invention, 1 make use of a removable air capsule of such
construction that instead of dipping the capsule in the liquids, gases etc. under
experiment, the liquids, gases etc. are placed into the capsule.
In the accompanying drawings,
Figure 1, represents a complete double thermometer
Figure 2, shews a cross section through line of Figure 1, and
Figures 3, 4, and 5 illustrate various shapes of air capsules, which are used for
special purposes
The iustiument consists of two U shaped tubes (6) and (b) fixed near each other
Behind
on a frame (a), said tubes (b) and (b) contain colored alcohol or the like.
the inner stem of the tubes there is a scale of opal or milk glass, to allow the level
to be measured. The glass for this scale is divided into three parts, so that the
height of the liquid may be ascertained from both sides. At the top of these
stems there are provided funnel shaped openings (d) and (d), for pouring in the
liquid. The outer stems are widened at (d') and (d), and provided at the top
with glass taps (e) and (e) which enable the operator to bring about a communica-
tion with the outer au. An india rubber tube (g) is attached to each horizontal
off tube (f).
ot
The air capsule (h) may be connected with the other end of this india rubber
tube. Two rings (1) and (1) or equivalent, are provided for the purpose
retaining said ai capsule in position. On the left hand side of Figure 1 in the
drawings (marked A) the preferable construction of the air capsule is represented
tube, is
In the glass receptacle (4) which at the bottom takes the shape of a
fused a tube (2) which is closed at the bottom and graduated so that the exact
quantity of liquid under experiment may be measured.
The sensitiveness of the instrument is such that it is seldom necessary to pour
the liquid direct into (7), it is sufficient, generally, to introduce a small insertion
glass (m) filled with the liquid so as to facilitate cleaning.
The air capsule may be replaced by a simple glass globular receiver, or by a
semi-globula one as shewn in Figures 4 and 5, or by the glass caso made in two
parts as shewn on the right hand side of Figure 1 and marked B.

page_text: In the latter, the air capsule (n) is fused to the cylinder (0) whilst its open end
is attached to the india rubber tube (7) another receptacle (p) also of a cylindrical
shape may be fixed under the polished edge of said cylinder (o).
When in use the U shaped tube (b) is filled with colored alcohol up to the middle
of the division which is marked by a notch, that can easily be seen. As soon ng
the air in the air-capsule expands under the influence of the heat of the liquid
under experiment the level of alcohol rises in the inner stem of the U shaped tube.
The enlarged portion (d) is formed to provide a chamber for the air which has
been displaced by the liquid so as to prevent the hydrostatic counter pressure, and
also to act as a safe guard against the squnting out of the alcohol though (f).
The tap (e) serves to equalise at once the levels in both the stems of the U shaped
tubes.
The double arrangement of the whole thermometer has for its object to enable
the operator to make simultaneously controlled or parallel experiments
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the saine is to be performed 1 declare that what I
claim 16:
Firstly. A double thermometer for experimental purposes based upon the
principle of an air thermometer and consisting essentially of a removable air
capsule (4) connecting with a U shaped tube (b) by means of an india rubber
tube (g) said tube (b) being provided with a scale (c) The air capsule contains a
glass tube (1) closed at the bottom and hermetically sealed to a larger glass
receptacle (k), said air capsule however may be replaced for special purposes by
capsules of other shapes similar to Figures 3, 4, and 5
Secondly. An air capsule of special construction consisting of a cylinder in two
parts in one of which the nii capsule ending at the tube may be fused
Thudly. The special construction of the milk glass scale, in three parts so as to
allow of the reading from both sides.
Dated this 6th day of May 1895.
W. D. ROWLINGSON,
172 Queen Victoria Street, London, E.C., Agent for the Applicaut.