AN IMPROVED MODE OF CONSTRUCTING THERMOMETERS
Year: 1854

page_text: LETTERS PATENT to Henry Blatter, of Paris, France, and of 4, South
Street, Finsbury, London, Watch Maker, for the Invention of "AN
IMPROVED MODE OF CONSTRUCTING THERMOMETERS."
PROVISIONAL SPECIFICATION left by the said Henry Blatter at the
Office of the Commissioners of Patents, with his Petition, on the 5th
April 1854.
I, HENRY BLATTER, of Paris, France, & of 4, South Street, Finsbury,
London, Watch Maker, do hereby declare the nature of my Invention for
"AN IMPROVED MODE OF CONSTRUCTING THERMOMETERS" to be as follows:-
My Invention consists in mechanical arrangements in the construction of a
thermometer for indicating distinctly and minutely the changes of temperature.
(1), Figures 1 & 2, represents a brass standard, to which is fixed the
extremity of a circular bar, half steel & half brass, which by its dilation or
contraction gives the motion to the upper end of a segment rack at its other
extremity (2), & thereby communicating to the catchings an eccentric move-
ment, serving to regulate precisely the course of the large hand. (3) repre-
sents a small wheel & rack for adjusting the thermometer according to the
temperature. (4), Figure 2, represents two sets of wheels and catchings,
causing the second hand to perform a rotation for each degree passed by
the large hand; thus, the smallest effect produced by the expansion or con-
traction of the bar causes the small hand to rotate, and thereby indicates the
slightest variation in the temperature.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Blatter in the Great Seal Patent Office on the 2nd
October 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BLATTER, of Paris, France, and of 4, South Street, Finsbury, London, Watch
Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of April, in the year of our Lord
One thousand eight hundred and fifty-four, in the seventeenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Henry Blatter, Her special licence that I, the said Henry Blatter, my
executors, administrators, and assigns, or such others as I, the said Henry
Blatter, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times times thereafter during
the term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "AN IMPROVED MODE OF CONSTRUCT-
ING THERMOMETERS," upon the condition (amongst others) that I, the said Henry
Blatter, by an instrument in writing under my hand and seal, should par-
ticularly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Blatter, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
thereof, reference being had to the Figures of the Drawing hereto annexed,
and to the letters marked thereon, that is to say:-
The new thermometer is constructed according to the principle of the
differential contraction and dilatation of metals, and consists of two strips
of steel and brass, united in their length and turned in the form of a
circle.
Figures 1 and 2 of the accompanying Drawing represent the construction
of the new thermometer, in which Figures the same letters of reference repre-
sent similar parts.
A, B, C, D, is the bi-metallic circle, the extremity D of which is per-
manently fixed to the plate forming the bottom of the thermometer, the other
extremity A receiving and reporting the contractible or expansive movement

page_text: of the circle, and being connected by means of the bent arm 6 to the lever of
a segmental rack T, moveable upon its axis a. The teeth of the rack T cog
with a central pinion P, upon the axis of which a spiral spring is fixed for
avoiding the loss of time caused by its retrograde movement, and a hand I is
set for marking the degrees of temperature upon a graduated dial, upon which
equivalent tables of the Reaumur centigrade and Fahrenheit scales may be
represented. The extremity A of the contractible circle is pierced to receive
the bent arm b, the set screw v serving to regulate the degree of tension of
the extremity A, and set the hand I to the proper position.
For regulating the thermometer, the back plate of the apparatus is made
of two concentric disks, turning one within the other. A rack h is fixed
upon the internal disk upon which the circle is set, and the external disk is
provided with a pinion R, which works the rack h. The axis of the pinion R
has a square end for the reception of a key, serving to turn the internal disk
to the right or left, and thereby lighten or release the circle and adjust the
hand I. In order to indicate the seconds or fractions of a degree, I set upon
the axis of the pinion P a wheel M, N, Figure 2, provided internally or
externally with teeth, which cogs with an intermediate wheel S, and the
latter cogs with the pinion P¹, the axis of which is provided with a hand i, to
indicate the fraction of a degree upon another smaller dial. The small
hand will perform a complete revolution while the large hand advances one
degree.
And having now described the nature of my said Invention, and the manner
in which the same is to be performed, I wish it to be understood that I do
not confine myself to the precise details herein laid down, so long as the
peculiar character of my Invention be retained; but what I claim is,-
First, the peculiar arrangement of a bi-metallic circle, composed of steel
and brass or other suitable metals, and the means of regulating the contractible
and expansible movement of this circle, as herein-before described and referred
to in the Figures of the Drawing.
Secondly, the transmission of the contractible or expansive movement of the
metallic circle by means of a rack and wheel work to a hand indicating the
degrees on a dial, as herein-before described and referred to in the Figures of
the Drawing.
Thirdly, the transmission of movement to a hand, indicating upon a separate
dial the seconds or fractions of a degree, as herein-before described and referred
to in Figure 2 of the Drawing.
Fourthly, the regulating with precision the position of the hand for the
degrees, by forming the back plate of the thermometer of two concentric disks,

page_text: turning one within the other and working by a key, as herein-before described
and referred to in the Figures of the Drawing.
In witness whereof, I, the said Henry Blatter, have hereunto set my
AL
L
hand
turning one within the other and working by a key, as herein-before described
and referred to in the Figures of the Drawing.
my
In witness whereof, I, the said Henry Blatter, have hereunto set hand
and seal, this Twenty seventh day of September, in the year of our
Lord One thousand eight hundred and fifty-four.
BLATTER. (L.S.)