Improvements in Lens-front or Magnifying Thermometers.
Year: 1892

page_text: Date of Application, 2nd Feb., 1892
Complete Specification Left. 2nd Nov., 1892-Accepted, 3rd Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in Lens-front or Magnifying Thermometers.
I, SAMUEL GEORGE DENTON of 25 Hatton Garden in the City of London,
Philosophical Instrument Maker, do hereby declare the nature of this invention to
be as follows:-
The object of my invention is to facilitate the reading of the divisions and
figures engraved on lens-front or magnifying thermometers (especially chemical
and clinical thermometers).
The thermometer tube I make with flattened bore and enamel strip at the back
of the bore in the usual way.
The lens (which as is well known only occupies a very small portion of the face.
or front of the tubing) I form directly over and in a continuous line with the bore
of the glass and on each side of the lens I make a flat surface (practically so)
on the glass, parallel with the flatness of the bore, on one of these surfaces I
engrave the divisions and on the other the figures. By this means both the
divisions and figures are more easily seen, they being engraved on a flat front
directly facing the eye, instead of on sloping sides running off at an angle as in
thermometers now constructed, which as a rule causes most part of the divisions
and figures to be out of sight when reading the thermometer.
I prefer also to flatten the back of the tubing behind the enamel, this prevents
the thermometers rolling.
Dated this 1st day of February 1892.
BOKMANY
COMPLETE SPECIFICATION.
Improvements in Lens-front or Magnifying Thermometers.
I, SAMUEL GEORGE DENTON, of 25 Hatton Garden, in the City of London,
Philosophical Instrument Maker, 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 :-
The object of my invention is to facilitate the reading of the divisions and
figures engraved on lens-front or magnifying thermometers (especially chemical
and clinical thermometers).
The thermometer tube I make with flattened bore and enamel strip at the back
of the bore in the usual way.
The lens (which as is well known only occupies a very small portion of the face
or front of the tubing) I form directly over and in a continuous line with the bore
of the glass and on each side of the lens I make a flat surface (practically so) on
the glass, parallel with the flatness of the bore, on one of these surfaces I engrave
the divisions and on the other the figures. By this means both the divisions and
figures are more easily seen, they being engraved on a flat front directly facing the
eye, instead of on sloping sides running off at an angle as in thermometers now
constructed, which as a rule causes most part of the divisions and figures to be out
of sight when reading the thermometer.
I prefer also to flatten the back of the tubing behind the enamel, this prevents
the thermometers rolling.
Figure 1 of the drawings annexed is a face view and Figure 2 an end view of a

page_text: thermometer constructed in the above manner. Figures 3, and 4 are cross sections
on a larger scale shewing examples of various forms in which my thermometer
tubes may be made.
Heretofore chemical and clinical thermometers have ordinarily been made of a
cross section such as shewn in Figure 5-the two opposite sides of the longitudinal
lens being continued downwards as straight lines inclined to one another as shewn
to meet the back and on one of these surfaces has been marked the divisions and
on the other the figures.
In my thermometer tubes in place of the surfaces on which the divisions and
letters are marked being continuations of (that is at tangents to) the curved lens
surfaces they are made at an angle to these curved surfaces and approximately
parallel with the bore as shewn.
One great advantage of flattening the tube in the way shewn is that the lens is
brought nearer to the bore and consequently if the tube gets twisted when a long
length of it is being drawn down to proper form it is of no consequence as the lens
and bore both twist together and the bore can always be seen plainly through
the lens.
In the drawings a is the lens, 6 the bore of the tube and c a strip of white
enamel.
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 :-
1. A lens front or magnifying thermometer tube with the surfaces on either side
of the lens approximately in the same plane and at an angle to the sides of the
lens in place of being continuations or prolongations of the sides of the lens as
heretofore.
2. A lens front or magnifying thermometer tube constructed substantially as
hereinbefore described and illustrated in the drawings annexed.
1000