IMPROVEMENTS IN THE ARRANGEMENT AND CONSTRUCTION OF GRADUATED SCALES FOR MRASUDING INSTRUMENTS.
Year: 1852

page_text: LETTERS PATENT to William Mackenzie, of Glasgow, in the County
of Lanark, North Britain, Publisher, and George Blair, of the
same place, Master of Arts, for the Invention of "IMPROVEMENTS
IN THE ARRANGEMENT AND CONSTRUCTION OF GRADUATED SCALES FOR
MRASUDING INSTRUMENTS.
"
Sealed the 30th March 1853, and dated the 5th October 1852.
PROVISIONAL SPECIFICATION left by the said William Mackenzie
and George Blair at the Office of the Commissioners of Patents,
with their Petition, on the 5th October 1859.
We, WILLIAM MACKENZIE, of Glasgow, in the County of Lanark,
North Britain, Publisher, and GEORGE BLAIR, of the same place,
Master of Arts, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE ARRANGEMENT AND CONSTRUCTION OF GRADUATED
SCALES FOR MEASURING INSTRUMENTS" to be as follows, that is to say:
This Invention relates to the marking of the graduated scales of
thermometers and other instruments of measurement on sheets of
elastic substances, such as vulcanized caoutchouc, with the intention
that such scale surfaces may be elongated or allowed to contract at
pleasure, to assist in the adjustment thereof to varying lengths compre-
hended between any two fixed points. The material which is preferred

page_text: for the body of the scales is vulcanized caoutchouc in thin sheets of
uniform thickness, and bleached or otherwise whitened or prepared, so
that the indications made thereon may be clearly perceptible. Such
indications may be formed or produced in various ways, the simplest
plan being to set up the lines of graduation, with their corresponding
literal references and numbers in type, the impressions being printed
upon the sheets either when the latter are slightly elongated or in their
natural condition of tension.. According to the ordinary construction
of thermometers the scales are required to be made expressly-for each
mercurial tube, in order to insure approximate accuracy, but by the
aid of elastic scales any number and variety of scales and tubes may
be at once adjusted to each other with equal accuracy, without any
special individual selection; that is to say, any two fixed points, as the
freezing and boiling points, being determined and marked upon the
tube, the elastic'scale may be stretched to bring the freezing and boiling
marks thereon to correspond exactly with the tube niarks, and if the
elastic material is of uniform width, thickness, and elasticity, all the
intermediate graduations will be found to agree with their corresponding
lines of mercurial traverse in the tube:
Vulcanized india-rubber is not materially affected by thermal or
atmospheric changes, and when soiled it may be washed. The adoption
of the elastic scales is also of very great advantage in admitting of the
enlargement of the number of index references beyond what is con-
veniently possible by the ordinary system of construction.
The same improvements are obviously applicable to various other
instruments. as barometers and steam guages.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Mackenzie and George Blair in the
Great Seal Patent Office, on the 5th April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we,
WILLIAM MACKENZIE, of Glasgow, in the County of Lanark, North
Britain, Publisher, and GEORGE BLAIR,-of-the-same-place,-Master-of-
Arts, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of October, in the year
of our Lord One thousand eight hundred and fifty-two, in the six-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said William Mackenzie and George
Blair, Her special licence that we, the said William Mackenzie and
George Blair, our executors, administrators, and assigns, or such others
as we, the said William Mackenzie and George Blair, our executors,
administrators, or 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, 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 THE ARRANGEMENT AND CONSTRUCTION CF GRADUATED SCALES FOR MEA-
SURING INSTRUMENTS," upon the condition (amongst others) that we, the
said William Mackenzie and George Blair, by an instrument in writing
under our hands and seals, 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 Seal Patent.
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that we, the said William Mackenzie and George
Blair, do hereby declare the nature of our Invention, and in what
manner the same is to be performed, to be particularly described' and
ascertained in and by the following statement, reference being had to
the Drawing hereunto attached, and to the letters and figures marked
thereon (that is to say):
:
. Our said Invention relates to the printing or marking of the gradu-
ated scales of thermometers and other instruments of measurement on
sheets of elastic substances, such as vulcanized caoutchouc, with the
intention that such scale surfaces may be elongated or allowed to
contract at pleasure, to assist in the adjustment thereof to varying
lengths, comprehended between any two fixed points. The material:
which we prefer for the body of the scales is vulcanized caoutchouc in.
thin sheets of uniform thickness,, and bleached or otherwise whitened
or prepared, so that the indications made thereon may be clearly per-

page_text: ceptible. Such indications may be formed or produced in various ways,
the simplest plan being to set up the lines of graduation, with their
corresponding literal references and numbers, in type, the impressions
being printed upon the sheets either when the latter are slightly
elongated or in their natural condition of tension. According to the
ordinary construction of thermometers the scales are required to be
made expressly for each mercurial tube in order to insure approximate
accuracy, but by the aid of clastic scales any number and variety of
scales and tubes may be at once adjusted to each other with equal
accuracy, without any special individual selection; that is to say, any
two fixed points, as the freezing and boiling points, being determined
and marked upon the tube, the elastic scale may be stretched to bring
the freezing and boiling marks thereon to correspond exactly with the
tube marks, and if the elastic material is of uniform width, thickness,
and elasticity, all the intermediate graduations will be found to agree
with their corresponding lines of mercurial traverse in the tube. Vul-
canized india-rubber is not materially affected by thermal or atmo-
spheric changes, and when soiled it may be washed. The adoption of
the elastic scales is also of very great advantage in admitting of the
enlargement of the number of index references beyond what is conve-
niently possible by the ordinary system of construction, and the same
improvements are obviously applicable to various other instruments, as
barometers and steam guages. The annexed Figure represents a
thermometer scale of this kind, as arranged with a greatly enlarged
series of fixed or marked points, in order to render the instrument of
superior value for chemical, meteorological, manufacturing, and other
uses. The caoutchouc or other elastic material which is employed is
or may be bleached, dyed, or coloured, in order to contrast strongly with
the ink or colour of the index points, as well as with the mercury or
other fluid in the thermometer tube. The sheets of the elastic material
are cut or shaped into slips or bands of such a form that when extended
they shall expand equally in every part. Parallel bands, as in the
accompanying Figure, from a, to b. answer sufficiently well for most
_practical purposes, but when extreme accuracy is wanted the pieces are
or may be cut so as to be broader or narrower in the middle, according
as they are to be drawn out or suffered to contract, after printing or

page_text: marking the index points and references thereon. These slips or
bands of elastic material, when thus prepared and cut to the necessary
dimensions, are each fixed in an adjusting frame fitted with sliding
holders, so that the material may be drawn out or extended, and kept
in the required state of extension when the scale is printed or marked
upon the stretched surface, either from types or an engraved plate, or
block or other arrangement. If the degrees to be measured are less
than those of the scale impression plate or type form, the slip is per-
mitted to contract to the required amount, and it is then glued or
otherwise firmly attached to the surface intended to carry the indications.
If, on the other hand, the degrees to be measured are larger than those"
on the imprinting or marking surface, the elastic material is still further
extended prior to being finally fixed down. In this latter case the pri-
mary stretching frame is unnecessary. When this Invention is applied
to thermometer scales, the imprinting plate or type form may be exactly
adapted to the irregularities of expansion in different fluids, and all the
impressions taken from it will be obviously applicable to any thermo-
meter in which that particular fluid is used, to whose law or determined
rate of expansion the original plate or imprinting surface has been
adapted. For example, this system answers for the obtainment of correct
indications from a spirit thermometer, the plate being formed so as to
make allowance for the known irregularities of the spirit expansion.
We may also remark that any required accuracy may be secured by
having a variety of plates of different lengths in the degrees or gradua-
tions, so as to render much expansion or contraction unnecessary
under any circumstances. It is a well known fact that few thermo-
meter tubes possess a perfectly uniform bore, and hence, in such
instances, the indications of the mercurial column are vitiated.
use of the elastic scales supplies a remedy for this evil, as the slips or
bands may be cut broader or narrower at the different points cor-
responding to the variations in the tube, so that the differential expansion
and contraction may coincide with the differential nature of the rise
and fall of the mercurial column. Generally, the tubes are slightly
conical or taper in their bore, so that on the amount of deviation from
uniformity being determined, the slips are cut to a corresponding taper.
This system of scale obviously allows of the introduction of much useful
The

page_text: information not given hitherto on thermometer scales. The material
which we especially recommend is almost indestructible, and unaffected
by heat and moisture,, so that no expansion or contraction can arise in
practice.,..
Having now described and particularly ascertained the nature of
our Invention, and the manner in which the same is or may be used
or carried into effect, we may observe, in conclusion, that we do not con-
fine or restrictou rselves to the precise details or arrangement which
we, have had occasion to describe or refer to, as many variations may
be made therefrom without deviating from the principles or main
features of our Invention; but what we consider to be novil and
original, and therefore claim as the Invention secured to us by the
herein-before in part recited Letters Patent, is,
First, tlie application and use of elastic substances in the construction
of permanent graduated scales for thermometers and measuring instru-
ments.
Second, the system or mode of securing accuracy in thermometrical
and other indications by proportioning the breadth and strength of the
elastic scale material to the deviations of the indicating tube.
Third, the system or mode of printing or marking graduated scales
when the material thereof is subject to extension for the purposes
herein-before described. .
Fourth, the application and use of graduated iniprinting surfaces, of
varying lengths of degrees, to correspond to the known expansion of the
various indicating fluids, as herein-before described.
In witness whereof, we, the said William Mackenzie and George
Blair, have hereunto set our hands and seals, this Second day
of April, in the year of our Lord One thousand eight hundred
and fifty-three.
WILLIAM MACKENZIE (L.S.)
GEORGE BLAIR.
(L.S.)