AN IMPROVED METHOD OF COLOURING THE ALCOHOL EMPLOYED IN THE CONSTRUCTION OF THERMOMETERS
Year: 1880

page_text: LETTERS PATENT to Edward Henry Torlesse Liveing, of 52, Queen Ann
Street, Cavendish Square, in the County of Middlesex, for an Invention of
"AN IMPROVED METHOD OF COLOURING THE ALCOHOL EMPLOYED IN THE
CONSTRUCTION OF THERMOMETERS."
PROVISIONAL SPECIFICATION left by the said Edward Henry Torlesse
Liveing at the Office of the Commissioners of Patents on the 29th September
1880.
EDWARD HENRY TORLESSE LIVEING, of 52, Queen Ann Street, Cavendish Square,
in the County of Middlesex. "AN IMPROVED METHOD OF COLOURING THE
ALCOHOL EMPLOYED IN THE CONSTRUCTION OF THERMOMETERS."
Dissolving in alcohol a powerfully fluorescent substance, known to chemists as
fluorescein (phthalein of resorcin), with the addition of a small quantity of some
alkali; I prefer ammonia. This solution when inserted in the tube of a thermometer
in the usual manner, and attached to a blackened scale as a back ground, reflects
an intense and beautiful green light, and the improvement over thermometers as
The
ordinarily constructed both as regards beauty and distinctness is evident.
ornamental effect is further heightened by constructing the bulb of the ther-
mometer in some distended form. I employ a spiral form, but some other forms
would answer equally well, it being borne in mind by the constructor that the
object of such a form is to display to the best advantage the double colour
possessed by the liquid, for though it reflects a green light it transmits a yellow
light.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Henry Torlesse Livesey in the Great Seal Patent Office
on the 29th March 1881.
EDWARD HENRY TORLESSE LIVEING, of 52, Queen Anne Street, Cavendish Square,
in the County of Middlesex. "AN IMPROVED METHOD OF COLOURING THE
ALCOHOL EMPLOYED IN THE CONSTRUCTION OF THERMOMETERS."
The said Invention consists of dissolving in alcohol a body known to chemists
as fluorescein, with the addition of a small quantity of some alkali, and in using
the fluorescent fluid thus produced in the construction of thermometers, in com-
bination with a black background and a bulb of some ornamental form, whereby
the improvements of greater distinctness in reading and of novel and more orna-
mental appearance are produced. And in order that the said Invention may be
properly understood I now proceed to set forth the manner in which it is to be
carried into effect.
The fluorescine (which may be obtained from chemical dealers under that name)
is to be dissolved in the alcohol (the strength of which is not important, and
methylated spirit of commerce answers well) in the proportion of one third of a
grain to the fluid ounce of spirit; this proportion can however be varied con-
siderably without much alteration in effect; the liquid thus produced is scarcely at
all fluorescent, but on the addition of a small quantity of an alkali it becomes
intensely so (I employ strong ammonia solution in the proportion of one drop to
the fluid ounce of spirit, but other alkalies may be used, and the exact proportion
is not at all material). The fluid thus obtained is introduced into the thermometer
tubes in the usual manner, these tubes being made with bulbs of various ornamental
forms, such as spiral or helical, or any other form that may be found convenient
(but no form is here claimed), the object of such bulbs being to display to the
best advantage the double colour possessed by the fluid which reflects a green light
but transmits a yellow light. The tubes thus made and filled are to be mounted
against a black scale (with white figures) as a dark background for the fluid, or
the dark background may be produced by varnishing the back of the tube with
black varnish or by a band of black enamel drawn in the glass of the tube in place
of the ordinary white enamel used for this purpose. If the thermometer be
intended for a registering one the index needle or needles must be made of some
reflecting material in order to show within the fluorescent fluid; in place of those
of black glass commonly employed I find white enamel glass answers well for this
purpose.
In witness whereof, I, the said Edward Henry Torlesse Liveing, have hereunto
set my hand and seal, this
day of March, in the year of our
Lord One thousand eight hundred and eighty one.
.
EDWARD H. T. LIVEING. (L.S.)