Improvements in Clinical Thermometers and in the Manufacture thereof.
Year: 1891

page_text: Date of Application, 11th Feb., 1891
Complete Specification Left, 2nd Oct., 1891-Accepted, 7th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Clinical Thermometers and in the Manufacture
thereof.
We, JAMES JOSEPH HICKS, of 8 Hatton Garden, in the County of Middlesex,
Meteorological Instrument Manufacturer, and HENRY PINCHETTI, of Lugano,
Canton of Ticino, in the Republic of Switzerland, Glass Blower, do hereby declare
the nature of this invention to be as follows:-
The invention has for its object improvements in clinical thermometers, whereby
we obtain a more open scale for a thermometer of given length, together with
greater strength and quickness of action than are obtained in clinical thermometers
as heretofore generally constructed.
Clinical thermometers as heretofore constructed have, according to one plan, been
provided with an index consisting of a short length of mercury separated by a
small air speck from the main column, and which, in the rise of the column, is forced
forward at the minimum distance from the latter, but which, on the descent of such
main column, is left behind at the maximum point reached. This is known as
Professor Phillips' plan of registering maximum temperatures.
According to another plan, the passage through the tube is contracted to a knife
edge at a point distant from half an inch to an inch more or less from the neck of
the bulb, by which means, after the column of mercury has risen to its maximum
height and that in the bulb begins to cool, the column in the tube above the con-
traction remains in its maximum position, thereby forming what is known as an
"indestructible" index, the mercury below the contraction contracting away there-
from; then, in order to re-set the thermometer for fresh use, it has to be swung
until the greater part of the mercury in the tube has passed the contraction and
the top of the column is below the lowest division of the scale. In this class of
thermometer, the tube being divided only above the contraction, the scale is
consequently not so open as if the entire tube were used for the scale; there is also
a considerable delay in the indication of the temperature by such class of thermo-
meter, as in forming such knife edge contraction, a chamber is first formed in the
tube by sealing the latter and then, by means of a blow pipe, heating it at the
required part, when the, air contained therein will become expanded by the heat
and will blow out the heated part of the tube and thereby form a chamber therein;
then, after exhausting the tube and again heating the part surrounding the said
chamber, the latter collapses so as to almost close the tube and thereby form the
knife edge division; the said chamber however is still left of such capacity as, in
some cases, to contain sufficient mercury to fill the upper part of the tube, or
nearly so; this chamber is surrounded by comparatively thick glass, and when the
thermometer is in use, the said chamber is generally placed outside of the mouth or
other part to which the thermometer is applied; it therefore takes a somewhat
considerable time before the thermometer correctly indicates the temperature, and
again such a thermometer is very liable to fracture at the knife edge contraction
during the process of preparing the scale; and after completion when swinging it
for the purpose of driving the mercury below the lowest division of the scale.
In another form of thermometer, a glass needle has been fixed in the centre of
the bulb and has had its.upper end arranged in such relation to the bore of the tube
as.to.partially throttle the entrance from the bulb, whereby, although the mercury
is,capable of passing the same when rising, it is prevented from returning to the
bulb when the mercury is cooling; this form of thermometer, although affording a
recording index, has not come largely into use as the bulb is unduly enlarged and
it has other drawbacks which render it objectionable.

page_text: Now, according to our invention, we avoid these disadvantages and obtain the
advantages hereinbefore named, by placing the knife edge contraction in close
proximity with the bulb, whereby we are enabled to use that portion of the tube
between the bulb and the knife edge contraction and thereby avail ourselves of the
entire length of the tube for forming thereon the scale.
In constructing a thermometer according to our invention, we first open out the
end of the tube to be joined with the bulb, and thereby form a small chamber we
then blow thereon a portion of "bulb cylinder" and, after having blown and formed
the bulb to its desired shape and size, we dip the tube in mercury and about half
fill the bulb therewith, all the above processes being those usually adopted. We
then seal the lower end of the bulb and open the top end of the tube, after which
we "boil" the mercury in the bulb so as to force out the air from the tube; then
when the mercury is seen to escape from the top end of the latter, we seal such top
end with wax. We then, after the mercury has cooled, heat, by a blow pipe, the
chamber joining the bulb, so as partially to contract it; the top end of the tube is
then unsealed and the mercury "boiled" in the usual way, after which we place
the tube in a vessel containing mercury where it is left until it becomes filled
therewith. We then, as usual, warm the partially formed thermometer, so as to be
enabled to mark the length of tube required for the scale; the tube is then cooled
and the top end closed with wax, after which we heat the top end of the tube and
there form a chamber; it is then unsealed and the top beyond the said chamber is,
by the aid of the blow pipe, drawn out to a fine tube or "splint" and then, by
warming the thermometer, we expand the mercury until it begins to pass through
such fine tube, after which we seal the tube just above the last mentioned chamber,
and at the same time break off the fine tube or "splint;" part of the mercury in
the bulb is then shaken into the chamber at the top of the tube, after which, by the
aid of a blow pipe, we complete the contraction in the chamber adjoining the bulb ;
the whole of the mercury is then shaken into the bulb, and the chamber at the top
end of the tube is used as a means of regulating the mercury in the thermometer
tube, according to the scale, and when this is effected the tube is sealed below the said
chamber, and the latter broken off in the usual manner.
The thermometer is then divided and has the scale applied in the ordinary
manner.
A thermometer constructed as herein described has all the mercury contained in
the bulb and in the chamber adjoining such bulb; in use therefore, all that part of
the thermometer containing the mercury is inserted in the mouth or other part of
which the temperature is required, and thereby the thermometer is much quicker in
its action than is the case with thermometers having a contracted chamber at a
distance from the bulb.
Dated this 11th dev of February 1801
JAMES J. HICKS.
HENRY PINCHETTI.
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Clinical Thermometers and in the Manufacture
thereof.
We, JAMES JOSEPH HICKS, of 8 Hatton Garden, in the County of Middlesex,
Meteorological Instrument Manufacturer, and HENRY PINCHETTI, of Lugano,
Canton of Ticino, in the Republic of Switzerland, 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, reference being had to the accompanying drawings, and to the figures
and letters marked thereon :-
The invention has for its object improvements in clinical thermometers whereby

page_text: we obtain a more open scale for a thermometer of given length, together with
greater strength and greater quickness of action, than are obtained in clinical
thermometers as heretofore generally constructed; the invention also relates to
improvements in the method of manufacturing such improved thermometer whereby
less risk of breakage and failure in the manufacture thereof is incurred, whilst the
mercury is retained in a cleaner condition, the bore is freer from moisture, and the
vacuum is more complete than if the ordinary method of manufacture were adopted
throughout.
In the accompanying drawings, which are made to an enlarged scale,
Figure 1 is a longitudinal section of a clinical thermometer provided with what is
known as Professor Phillips' plan of registering maximum temperatures.
Figure 2 is a side view partly in section of a clinical thermometer provided with
what is known as an "indestructible" index.
Figure 3 is a side view partly in section of a clinical thermometer having the
entrance from the bulb into the bore contracted or throttled by a glass needle or
"splint" fixed in the centre of the bulb, and
Figure 4 is a side view partly in section of a clinical thermometer constructed
according to our invention.
Clinical thermometers as heretofore constructed have, according to Professor
Phillips' plan, represented at Figure 1, been provided with an index consisting of a
short length of mercury a separated by a small air speck from the main column c,
and which index a, in the rise of the main column c, is forced forward at the
minimum distance from the latter, but which index, on the descent of such main
column, is left behind at the maximum point reached.
Clinical thermometers of the character represented at Figure 2 have also
heretofore had the passage through the tube d contracted to what is known in the
trade as a "knife edge" contraction at a point e distant from about half an inch to
an inch, more or less, from the neck of the bulb g, by which means, after the
column of mercury has risen to its maximum height, and that in the bulb and below
the contraction begins to cool, the column in the tube d above the contraction e is
cut off from the main body of mercury and remains in its maximum position, thereby
forming what is known as an "indestructible" index, the mercury below the con-
tractione contracting away therefrom; then, in order to re-set the thermometer
for fresh use, it has to be swung until the greater part of the mercury in the tube d
above the contraction e has descended below the latter and the top of the column is
below the lowest division of the scale.
"
In this class of thermometer, the tube being divided only above the contraction,
the scale is consequently not so open as if the entire tube above the neck of the
bulb were available for the scale; there is also a considerable delay in the indication
of the temperature by such class of thermometer, as in forming such "knife edge
contraction, a chamber is first formed in the tube at the point required by sealing
the latter, and then, by means of a blow pipe, heating it at the required part, when
the air contained therein will become expanded by the heat and will blow out the
heated part of the tube and thereby form a chamber therein, then, after exhausting
the tube and again heating the part surrounding the said chamber, the latter
collapses so as to almost close the tube and thereby form the "knife edge "division ;
the said chamber however is still left of such capacity as, in some cases, to contain
sufficient mercury to fill the upper part of the tube, or nearly so; this chamber is
also surrounded by comparatively thick glass, and when the thermometer is in use,
the said chamber is generally placed outside of the mouth or other part to which
the thermometer is applied; it therefore takes a somewhat considerable time
before the thermometer correctly indicates the temperature, and again, such a
thermometer is very liable to fracture at the "knife-edge" contraction during the
process of preparing the scale and after completion when swinging it for the purpose
of driving the mercury below the lowest division of the scale.
In the form of thermometer shown at Figure 3, a glass needle or splint / has

page_text: heretofore been fixed in the centre of the bulb g, and has had its upper end arranged
in such relation to the bore of the tube d as to partially throttle the entrance from
the bulb g, whereby although the mercury is capable of passing the saine when
rising, it is prevented from returning to the bulb g when the mercury is cooling;
this form of thermometer, although affording a rocording index, has not come
largely into use as the bulb y is unduly enlarged there is great difficulty in perfectly
withdrawing all the air therefrom which makes it almost worthless and it has other
drawbacks which render it objectionable.
Now according to our invention, as represented at Figure 4, we avoid these
disadvantages and obtain the advantages hereinbefore named by placing the "knife
edge" contraction e in close proximity with the bulb y, whereby we are enabled to
use that portion of the tube a heretofore existing between the bulb g and the knife
edge contraction e, and thereby avail ourselves of the entire length of the tube d
for forming thereon the scale.
In constructing a thermometer according to our invention, we first by the aid of
the blow pipe, open out the end of the tube d to be joined with the bulb, and
thereby form a small chamber d' as usual; we then blow thereon a portion of bulb
"cylinder" and, after having blown and formed the bulb to its desired shape and
size, we dip the tube in mercury and about half fill the bulb therewith, all the
above processes being those usually adopted in the making of other clinical
thermometers. We then, according to our invention, seal the lower end of the
bulb 9 and open the
top end of the tube d, after which we "boil" the mercury in
the bulb g, so as to force out the air from the tube d; then, when the mercury.
is
seen to escape from the top end of the latter, instead of placing it in a cup of
mercury to fill as usual, we seal such top end with wax. We then, after the
mercury has cooled and returned to the bulb g, heat, by a blow pipe, the chamber d¹
adjoining the bulb, so as partially to contract it; the reason for only partially
forming the contraction at this stage is that, supposing the contraction were fully
formed at this time, then, in the second boiling of the tube, which is necessary
to fill the bulb, there would be great risk of the bulb bursting, whilst on the other
hand, on placing the thermometer in mercury after the said boiling, the mercury
would be unable to enter the bulb on account of the resistance caused by the con-
traction. The top end of the tube d is then unsealed and the mercury "boiled" in
the usual way, after which we place the tube in a vessel containing mercury, where
it is left until it becomes filled therewith. We then as usual warm the partially
formed thermometer, so as to be enabled to mark the length of tube d required for
the scale and to see that the same is of the desired length, the tube d is then cooled
and the top end closed with wax, after which we heat the top end of the tube d
above the part required for the top end of the thermometer when finished and there
form a chamber; it is then unsealed and the top of the tube d, beyond the said
chamber, is by the aid of the blow pipe, drawn out to a fine tube or "splint," and
then by warming the thermometer we expand the mercury, until it begins to pass
through such fine tube, thereby driving the air out of the tube, after which we seal
the tube d just above the last mentioned chamber and at the same time melt off the
fine tube or "splint ;" part of the mercury in the bulb g is then shaken into the
chamber at the top of the tube d, after which, by the aid of a blow pipe, we
complete the contraction e in the chamber d adjoining the bulb g; the whole of the
mercury is then shaken into the bulb and the chamber at the top end of the tube
is used, in the ordinary manner, as a means of regulating the mercury in the
thermometer tube according to the scale, and when this is effected the tube is
sealed below the said chamber and the latter melted off in the usual manner.
-
The thermometer is then divided and has the scale applied in the ordinary
marner.
A thermometer constructed as herein described has all its mercury contained in
the bulby and in the chamber d' adjoining such bulb; in use therefore all that
part of the thermometer containing the mercury is inserted in the mouth, or other

page_text: part of which the temperature is required, and thereby the thermometer is much
quicker in its action than is the case with thermometers having a contracted
chamber at a distance from the bulb.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A clinical thermometer having the "knife edge" contraction for producing
the indestructible index in close proximity with the bulb, substantially as herein
shown and described and for the purpose stated.
2. A clinical thermometer having the "knife-edge" contraction for producing
the indestructible index in close proximity with the bulb, and the scale extending
over a greater length of the tube than heretofore, substantially as herein shown and
described and for the purpose stated.
3. The manufacture of the improved clinical thermometer of the character herein
described by the following process, 1st, forming a small chamber at one end of the
length of tube, 2nd, blowing the bulb on to such chamber, 3rd half filling the bulb
with mercury, as usual, 4th, sealing the lower end of the bulb, 5th, opening the top
end of the tube, 6th boiling the mercury in the bulb to force out the air from the
tube, 7th, sealing the top end of the tube with wax, 8th partially forming the con-
traction for the indestructible index in close proximity with the bulb by heating
the small chamber adjoining the bulb, 9th, unsealing the top end of the tube,
10th, boiling the mercury in the usual way, 11th, placing the tube in a vessei
containing mercury to fill, 12th, warming the partially formed thermometer and
marking length of tube required for the scale, as usual, 13th, cooling tube and
closing top end thereof with wax, 14th, forming a chamber at top end of tube
above the part required for the finished thermometer, 15th, unsealing top end of
tube and drawing it out to a fine tube or splint," 16th, warming thermometer to
drive out air therefrom, 17th sealing tube above chamber at top end thereof, and at
same time melting off the fine tube or "splint," 18th, shaking part of mercury in
bulb into chamber at top end of tube, 19th completing by a blow pipe the con-
traction in the chamber adjoining the bulb, 20th shaking all the mercury into the
bulb, 21st, regulating the mercury in the thermometer tube according to the scale,
22nd sealing the tube below the chamber at top end and melting off said chamber
in the usual manner, 23rd dividing the tube and applying the scale in the ordinary
way substantially as herein described.
Date October On3 1001
66