IMPROVEMENTS IN MAXIMUM REGISTERING TURPMONSTERS
Year: 1871

page_text: LETTERS PATENT to Louis Marino Casella, of Hatton Garden, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN
MAXIMUM REGISTERING TURPMONSTERS
"
PROVISIONAL SPECIFICATION left by the said Louis Marino Casella
at the Office of the Commissioners of Patents, with his Petition,
on the 20th October 1871.
I, LOUIS MARINO CASELLA, of Hatton Garden, in the County of
Middlesex, do hereby declare the nature of the said Invention for
" IMPROVEMENTS IN MAXIMUM REGISTERING THERMOMETERS, to be as
follows:-
"
In maximum registering thermometers as generally made there is a
small portion of the column of mercury separated from the remaining
portion by a small air speck, the action being that when the column of
mercury rises and again falls the portion separated by the air speck, and

page_text: which is usually called the "index," remains at the highest point, and
therefore registers the maximum temperature. When the thermometer
is again required for use, this small portion or index is caused to
descend by swinging the thermometer or otherwise, and it often
happens that in this operation the index reaches the ordinary enlarged
part of the bore near the bulb, and joins the main portion of the
mercury, thus allowing the air speck to escape. The thermometer is
then no longer a registering thermometer.
Now the object of my Invention is to avoid all chance of the air
speck escaping in ordinary use, and I effect this by preventing the index
descending below a certain determined point. For this purpose I enlarge
the bore at such determined point so that when the mercury which
constitutes the index reaches the said point it becomes shortened in
length and more globular in form, and as it has a natural tendency to
retain this globular form it does not descend into the part of the bore
of ordinary diameter below.
In some cases I contract the bore immediately below the cnlarged
part to increase the effect of the enlargement.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Louis Marino Casella in the Great Scal Patent
Office on the 11th April 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
MARINO CASELLA, of Hatton Garden, in the County of Middlesex,
send greeting.
› WHEREAS Her most Excellent Majesty Queen Victoria, by Her:
Letters Patent, bearing date the Twentieth day of October, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Louis Marino Casella, Her special
licence that I, the said Louis Marino Casella, my executors, adminis
trators, and assigns, or such others as I, the said Louis Marino
Casella, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,

page_text: use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN MAXIMUM REGISTERING THERMOMETERS," upon the condition
(amongst others) that I, the said Louis Marino Casella, my executors or
administrators, by an instrument in writing under my, or their, or
one of their hands and scals, should particularly 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 Scal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Louis Marino Casella, 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
accompanying Drawings, that is to say :—
2
In maximum registering thermometers as generally made there is a
small portion of the column of mercury separated from the remaining
portion by a small air speck, the action being that when the column of
mercury rises and again falls the portion separated by the air speck, and
which is usually called the "index," remains at the highest point, and
therefore registers the maximum temperature. When the thermometer
is again required for use, this small portion or index is caused to
descend by swinging the thermometer or otherwise, and it often
happens that in this operation the index reaches the ordinary enlarged
part of the bore near the bulb, and joins the main portion of the mercury,
thus allowing the air speck to escape. The thermometer is then no longer
a registering thermometer.
Now the object of my Invention is to avoid all chance of the air
speck escaping in ordinary use, and I effect this by preventing the
index descending below a certain determined point. For this purpose
I enlarge the bore at such determined point, so that when the mercury
which constitutes the index reaches the said point it becomes shortened
in length and more globular in form, and as it has a natural tendency to
retain this form it does not descend into the part of the bore of ordinary
diameter below.
In some cases I contract the bore immediately below the enlarged

page_text: The annexed Drawing is a view of one of my improved thermometers
on an enlarged scale.
a, a,
is the bore of ordinary diameter; b is the enlarged portion of the
bore which prevents the "index" descending to the portion of the bore
below; c is a contracted portion of the bore immediately below the
enlarged part b. The Drawing shews the index in position in the
enlarged part.
In witness whereof, I, the said Louis Marino Casella, have here-
unto set my hand and scal, this Tenth day of April Onc
thousand eight hundred and seventy-two.