Improvements in Clinical and other Registering Thermometers.
Year: 1899

page_text: Date of Application, 11th Jan., 1899
Complete Specification Left, 11th Oct., 1899-Accepted, 11th Nov., 1899
Improvements in Clinical and other Registering Thermometers.
I, LUIGI FEDELE COMITTI, of 69, Mount Pleasant, in the County of London,
Scientific Instrument Maker, do hereby declare the nature of this invention to be
as follows:-
-
In maximum registering thermometers as generally made there is a small
portion of mercury, contained in a bore of very fine diameter in the case of clinical
thermometers of the kind, which is separated from the column of mercury after
it has risen to the maximum and as it again falls, the point where the division
takes place being a constriction of the bore, which constriction by relieving the
column of mercury above of so much of its weight stays its fall and the mercury
below the constriction being unsupported returns to the bulb or reservoir; this
remaining portion of the column constitutes the "index" and indicates the maxi-
mum degree reached.
Various constructions have been proposed for facilitating this severance of the
column of mercury and for increasing sensitiveness of this class of instrument and
the delicacy of the indications.
In what is known as Professor Phillip's plan of construction of registering
maximum temperature thermometers a short length of index thermometer mer-
cury in a fine bore is separated from the main column of mercury by an air speck
and the air speck when the mercury rises is carried up and on the recession of
the mercury is left at the highest point and there registers the maximum tem-
perature.
When the thermometer is again required for use this small portion of mercury
is caused to descend by swinging or otherwise bringing centrifugal force to bear
on the mercury to make it return to the ordinary enlarged part of the bore near
the bulb.
The inconvenience attending these constructions is the liability of the index
portion not only to be forced back to the desired position in the enlarged part of
the tube, but to pass into the bulb itself and the air speck was lost, the ther-
mometer ceasing to register.
In 1871 a method was patented whereby the air speck was trapped at an
enlargement of the bore at a determined point whereby the mercury of the index
was caused to assume a globular form with consequent disinclination to further
pass down the bore toward the bulb below.
According to another method the bore of the tube is contracted to a knife edge
at a determined point, a distance of from half an inch to an inch from the neck
of the bulb, whereby the column of mercury, having by expansion risen to its
maximum height the mass of mercury in the bulb in cooling contracts and with-
draws into the bulb the column being severed at the knife edge that offering
greater resistance to the return of the "index" portion of the column. When
the index portion is desired to be lowered this is effected by a peculiar swinging
or jerking action, well understood.

page_text: Movable parts have been employed in the bore in the nature of valves to permit
rise and prevent fall of the mercury without the aid of “swinging" to overcome
such detaining means.
Again it has been proposed to overcome some of the difficulties and incon-
veniences attendant on the making and use of clinical thermometers by placing
the knife edge contraction for producing the index in close proximity to the bulb.
I am also aware that it has been proposed to provide a plurality of contractions
in the bore of the thermometer of this class so as to enable the contractions to be
less acute and the passage of the mercury past such contractions when the instru-
ment is swung for resetting, to be facilitated.
According to another proposed construction the index bore of very fine dimen-
sions at a point below the graduated indicating portion of the tube becomes some-
what suddenly merged into one of larger diameter or into a larger cavity or cavi-
ties between the bulb and such indicating tube so that the enlarged bore or cavity
may contain a comparatively considerable weight of mercury with a contraction
or constriction in this enlarged bore to restrain the return of the index mercury
to the bulb during contraction.
Again it has been proposed to further improve such thermometers by providing
a mercury chamber consisting of a swelling or enlargement of the ordinary bore
at a point above the constriction or contraction referred to, so as to facilitate the
use of the modern constructions using a small bulb and a very fine bore with the
attendant advantage of quick registration of temperature owing to the utiliza-
tion of the capillary attraction of the fine bore for the mercurial column. The
effect of this device claimed being that shaking the thermometer to reset the same
for use the body of mercury within said chamber will act to force some of the
mercury down through the contraction and at the same time draw some of the
mercury in the bore down into the chamber, enabling the thermometer to be
reset with very little effort, and leaving its sensitiveness and accuracy unimpaired.
Now according to the present invention the very fine indicating tube of the ther-
mometer is made as usual and the contraction is provided in the ordinary manner
at a suitable distance below in order to restrain the return of the index column
of mercury to the bulb and to cause the severance of such column-to form the
indestructible index-from the main body of mercury, but I form below and in
close proximity to the said constriction or contraction in the bore a chamber or
enlargement for lodgement of mercury in the use of the same, and when contrac-
tion thereof takes place the mercury that was filling this chamber instead of
remaining lodged therein, passes wholly or mainly down the bore to the main
body of mercury. In the shaking or swinging of the thermometer to reset it for
fresh use this chamber much facilitates the return of the mercury of the index
portion by the enlarged outlet provided and by serving as a receptacle for the same
to lodge in and besides increases the sensitiveness of the instrument.
111
•
1000
Improvements in Olinical and other Registering Thermometers.
I, LUIGI FEDELE COMITTI, of 69, Mount Pleasant, in the County of London,
Scientific Instrument Maker, do hereby declare the nature of this invention and

page_text: in what manner the same is to be performed to be particularly described anu
ascertained in and by the following statement:—
This invention relates to maximum temperature registering thermometers, and
it has for its object to provide a thermometer of the character described wherein
the return of the mercury to the bulb, after having indicated the temperature,
is greatly facilitated.
To this end my invention consists in the features and in the construction,
arrangement and combination of parts, hereinafter described and particularly
pointed out in the claim following the description.
In registering thermometers of the type referred to, as generally constructed,
there is a small portion of mercury contained in a bore of very fine diameter in
the thermometer tube which is separated from the column of mercury after it has
risen to the maximum point and as it again falls, the point where the division
takes place being a constriction of the bore, which constriction by relieving the
column of mercury above of so much of its weight stays or retards its fall and
the mercury below the constriction being unsupported returns to the bulb or
reservoir. This remaining portion of the column constitutes the index and in-
dicates the maximum degree attained.
Various constructions have been proposed for facilitating the severance of the
column of mercury, and for increasing the sensitiveness of this class of instru-
ments and the delicacy of the indications.
In one plan of construction, a short length of index mercury in a fine bore is
separated from the main column by an air speck or bubble, and the air speck when
the mercury rises is carried up and on the recession of the mercury is left at the
highest point and there registers the maximum temperature. When the ther-
mometer is again required for use, this small portion of mercury is caused to des-
cend by swinging or otherwise bringing centrifugal force to bear on the mercury
to make it return to the ordinary enlarged part of the bore near the bulb. The
inconvenience attending this and similar constructions is the liability of not only
forcing the index portion of the mercury back to the desired position in the
cularged part of the tube but also to force it into the bulb itself and the air
speck thereby becomes lost and the thermometer ceases to register.
Another method has been devised whereby the air speck is trapped at an
enlargement of the bore at a determined point, whereby the mercury of the index
is caused to assume a globular form with the consequent disinclination to further
pass down the bore to the bulb below.
According to another method, the bore of the tube is contracted to a knife edge
at a determined point at a distance of from half an inch to an inch from the neck
of the bulb, whereby the column of mercury, having by expansion risen to its
maximum height, in cooling contracts and withdraws into the bulb, the columu
being separated at the knife edge which offers greater resistance to the return of
the index portion of the column. When the index portion is desired to be
lowered this is effected by a peculiar swinging or jerking action which is well
understood.
Moveable parts have also been employed in the bore in the nature of valves to
permit the rise and prevent the fall of the mercury without the aid of swinging
to overcome such detaining means.
Again it has been proposed to overcome some of the difficulties and incon-
veniences attendant upon the manufacture and use of such thermometers by
placing the knife edge contraction for producing the index in close proximity to
the bulb.
I am also aware that it has been proposed to provide a plurality of contractions
in the bore of the thermometer so as to enable the contractions to be less acute
and to facilitate the passage of the mercury therepast when the instrument is
swung for resetting.
According to another proposed construction the index bore of very fine dimen-

page_text: sions at a point below the graduated indicating portion of the tube becomes
somewhat suddenly merged into one of larger diameter or into a larger cavity or
cavities between the bulb and such indicating tube so that the enlarged bore
or cavity may contain a comparatively considerable weight of mercury with a
contraction or constriction in this enlarged bore to restrain the return of the mer-
cury to the index bulb during contraction.
Again it has been proposed to further improve such thermometers by providing
a mercury chamber consisting of a swelling or enlargement of the ordinary bore
at a point above the constriction or contraction referred to so as to facilitate the
use of the modern constructions using a small bulb and very fine bore with the
attendant advantage of quickly registering the temperature owing to the utiliza-
tion of the capilliary attraction of the fine bore for the mercurial column, the
alleged effect of this device being that on shaking the thermometer to reset the
same for use the body of mercury in said chamber will act to force some of tl e
mercury down through the contraction and at the same time draw some of t.
mercury in the bore down into the chamber, and enabling the thermometer to
be reset with very little effort, and leaving its sensitiveness and accuracy un-
impaired.
According to the present invention, a very fine indicating tube of the ther-
mometer is made as usual, and the contraction is provided in the ordinary manner
at a suitable distance below in order to restrain the return of the index column
of mercury to the bulb, and to cause the separation of such column from the
main body of mercury to form an indestructible index. I form, however, below
and in close proximity to the said constriction or contraction in the bore a cham-
ber or enlargement of the mercury and when contraction of the latter occurs the
mercury in said chamber instead of remaining lodged therein passes wholly or
mainly down the bore to the bull. In shaking or swinging the thermometer to
reset it for further use, this chamber greatly facilitates the return of the mercury
of the index portion by the enlarged outlet provided, and serves as a receptacle
for the mercury to lodge in that is to say; by making the mercury so much larger
near the contraction it enables a much larger contraction to be used without im-
pairing the operation of that contraction and thereby facilitates the resetting
whilst preserving the registering function of the thermometer.
Referring to the drawing wherein is illustrated a view in elevation of my
improved thermometer, the numeral 1 indicates the glass thermometer tube;
2, the bore therein, and 3 the constriction or contracted portion of the bore con-
structed in the usual manner. A chamber or enlargement 4 is formed in the bore
below and in close proximity to said constriction or contraction for lodgment
of mercury, and when contraction of the latter occurs the mercury in said chamber
instead of being held therein passes either wholly or partially down the bore to
the main body of mercury in the usual bulb 5.
In shakeing or swinging the thermometer to reset it in said chamber, it facili-
tates the return of the index portion of the mercury through the enlarged outlet
and serves as a receptacle for the same to lodge in.
The numeral indicates the fine graduated index constructed as usual for indi-
cating the height of the index portion of the mercury.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A maximum temperature registering thermometer comprising a ther-
mometer tube provided with a fine index and having a bore formed with a con-
striction or contracted portion at a point below the index, and a chamber or
enlargement formed in the base beneath the constriction or contraction and in
proximity thereto, substantially as described and for the purposes specified.
2. In a clinical or like registering thermometer the herein described construc-

page_text: tion and arrangement of parts so that by making the mercury so much larger
near the contraction it enables a much larger contraction to be used without im-
pairing the operation of that contraction and thereby facilitates the resetting
whilst preserving the registering function of the thermometer, as set forth.
Dated the 11th of Ontahan 1900
WM. BROOKES & SON,
55 and 56, Chancery Lane, London, Agents for the Applicant.