Year: 1886

page_text: Date of Application, 20th July, 1886.
Complete Left, 20th Apr., 1887.
Complete Accepted, 20th May, 1887.
I, PAUL WARD, of Olga Villa, Hurlingham Lane, Fulham in the County of
Middlesex, Electrician, do hereby declare the nature of my said invention to be as
follows:-
This invention consists in improvements in Thermometers whereby many of the
disadvantages attendant on the present use of mercury and spirit of wine are avoided.
Mercury cannot be used below a certain temperature and spirit is small in its
expansive power and unsuitable for such thermometers as are known as minimum
registering and bath thermometers from the fact that it is unequal in its expansion
and cannot be coloured with a brilliant colour which will not, in time fade.
My improvement consists in using a fluid whose freezing point is lower than that
of spirit and which is non inflammable and which is capable of dissolving an
elementary substance and holding it permanently in solution, giving it a rich crimson
colour which is incapable of fading.
In carrying out my invention I employ the tetra chloride of carbon as my
expansible fluid and I use the metalloid Iodine dissolved in suitable proportion
therein for the colouring matter.

page_text: I, PAUL WARD, of Olga Villa, Hurlingham Lane, Fulham, in the County of
Middlesex, Electrician, 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 consists in improvements in thermometers, whereby many of the
disadvantages attendant upon the employment of mercury or of the spirit usually
employed within the bulb as at present are avoided. Hitherto in the construction of
thermometers mercury has been used for indicating temperatures but the same cannot
be employed for indicating temperatures below a certain degree and spirit of wine has
been used for indicating temperatures below the freezing point of mercury and also
for the manufacture of what are known as minimum registering thermometers.
Among the many disadvantages consequent upon the employment of spirit generally
used are the following:-the unequal expansion for various temperatures, the
sluggishness of action due to inferior conduction of heat, the small co-efficient of
expansion for a given increase of temperature and the danger during manufacture
owing to the inflammability of the material.
By substituting tetrachloride of carbon for the beforementioned spirit or mercury,
I avoid all these disadvantages, as it is an absolutely non-inflammable liquid, the
equality of the expansion of which approaches that of mercury; its rapidity of
conduction of heat is efficient and its co-efficient of expansion is greater than that of
the fluids hitherto employed for the said purpose.
By the use of tetrachloride of carbon the terrible disease with which makers of
mercurial thermometers are affected is avoided.
A further advantage to be obtained by the use of tetrachloride of carbon is that the
extreme thinness of this fluid allows of its being employed in instruments of the
smallest bore.
In spirit thermometers a colouring matter has been employed to render the liquid
more readily visible but the same has always been liable to fade in course of time
from the unavoidable exposure to light, however, I am enabled to give the tetrachloride
of carbon a brilliant colour by dissolving a quantity of Iodine therein; this is
permanently held in solution, it cannot be decomposed, and is totally unaffected
by light.

page_text: Thermometers, the fluid within which is coloured as hereinbefore described will be
found specially suitable for clinical purposes.
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 :-
1st. The employment of tetrachloride of carbon in thermometers, substantially and
for the purpose herein before described.
Secondly. The employment of tetrachloride of carbon in combination with Iodine,
for producing a brilliant colour by being held permanently in solution, substantially
as, and for the purpose hereinbefore described.
PAUL WARD,
Inventor.