IMPROVEMENTS IN THE SPIROMETER
Year: 1875

page_text: LETTERS PATENT to Henry Charles Mayer, of Pall Mall, in the
County of Middlesex, Surgeon, for the Invention of "IMPROVEMENTS
IN THE SPIROMETER."
Scaled the 23rd April 1875, and dated the 23rd January 1875.
PROVISIONAL SPECIFICATION left by the said Henry Charles Mayer
at the Office of the Commissioners of Patents, with his Petition,
on the 23rd January 1875.
I, HENRY CHARLES MAYER, of Pall Mall, in the County of Middlesex,
Surgeon, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE SPIROMETER," to be as follows:
This Invention has for its object improvements in the "spirometer,
rendering the same portable and specially useful for medical purposes.
In carrying out the object of my said Invention I proceed as follows:
-I construct a vessel made of any suitable material of measured
capacity, say, of about twenty-five cubic inches. Connected to this

page_text: vessel is a mercurial tube which fits air-tight into the vessel, the mouth
inside terminating in a corrugated metal top. A tube with mouth-piece
is also connected to the vessel.
When using the instrument the person blows through the air tube,
and of course in doing so increases the pressure of the air inside the
vessel, and the additional pressure acting on the mercury in the mercurial
tube forces the mercury up the tube. The said tube is graduated so as
to show the additional pressure and also the amount blown into the
vessel, so that the same will at once be seen by noting the height of
mercury the additional pressure and also the amount of air blown into
the vessel.
To prove the correctness of the instrument I supply a small pump,
graduated, by means of which air can be forced into the vessel in the
quantity of from one cubic inch at one time up to any desired pressure.
The pressure indicating the volume of air at any time can be seen.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Charles Mayer in the Great Seal Patent 2
Office on the 23rd July 1875.,
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
CHARLES MAYER, of Pall Mall, in the County of Middlesex, Surgeon,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent; bearing date the Twenty-third day of January, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Henry Charles Mayer, Her
special licence, that I, the said Henry Charles Mayer, my executors,
administrators, and assigns, or such others as I, the said Henry Charles

page_text: Mayer, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 Inven-
tion for "IMPROVEMENTS IN THE SPIROMETER," upon the condition (amongst
others) that I, the said Henry Charles Mayer, my executors or admini-
strators, by an instrument in writing under my, or their, or one of
their 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 causo 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 Charles Mayer, 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 :-
This Invention has for its object improvements in the spirometer,
rendering the same portable and specially useful for medical purposes.
In carrying out the object of my said Invention I procced as follows:
-I construct a vessel made of any suitable material of ascertained
capacity, say, of about twenty-five cubic inches. Connected to this
vessel is a mercurial tube which fits air-tight into the vessel, the mouth
inside terminating in a corrugated (or non-corrugated) metal top
(although any top may be dispensed with under certain circumstances).
A tube with mouth-piece is also connected to the vessel.
When using the instrument the person blows through the air tube,
and of course in doing so increases the pressure of the air inside the
vessel, and the additional pressure acting on the mercury in the
mercurial tube forces the mercury up the tube. The said tube is
graduated so as to show the additional pressure and also the amount
blown into the vessel, so that the same will at once be seen by noting
the height of mercury, the additional pressure, and also the amount of
air blown into the vessel.
To prove the correctness of the instrument I supply a small pump,

page_text: graduated, by means of which air can be forced into the vessel in the
quantity of from one cubic inch at one time up to any desired pressure..
The pressure indicating the volume of air at any time can be seen.
a sectional elevation of Figure 1.
Figure 3 represents an clevation of a modified form of my improved
spirometer; Figure 4 is a view of one end of Figure 3.
:
Figure 5 represents the adaptor.
In these Figures A represents vessel or chamber of measured capacity;-
B is the mercurial tube in connection with the said chamber (said
mercurial tube being self registering or otherwise), said tube fitting air-
tight by means of adaptor (B') into the vessel or chamber A; C represents
the mouth with metal top to which the mercurial tube is in free com-
munication. This metal top, if desired, need not be used. D is the tubo
with mouth-piece connected to the vessel or chamber (A); D' is cock or
valve to open or close the chamber (A) from the tube and mouth-
piece D; E is the cylinder or barrel of force pump; F is plug or piston
working air-tight in the cylinder or barrel E; G is spindle to which
piston or plug F is secured, said spindle being furnished with handle, as
shown, to admit of working the pump; H is part connected to vessel or
chamber A in which the pump fits free to move; the lower part of H is
furnished with cock (H') which opens or closes the communication with
chamber A and thereby governs the exit or entrance of air forced into
the chamber A.

page_text: The action is as follows:-Air is forced into the vessel A by means of
the pump (the cock D' being closed). The spindle G is graduated in
inches so that a known quantity of air when the piston is forced down
passes through the opening f into the opening f' (the cock H' being
open) into the chamber A and the mercury rises in the tube indicating
the amount of air forced into the vessel. When the desired. pressure of
air in the chamber A is obtained the cock H¹ is turned off (the cock D₁
being previously turned off) so that the air introduced into the vessel A.
is confined therein. The cock D₁ being opened the air passes from the
chamber A, the mercury falls the zero on the scale B³, being then (when
temperature renders it necessary) brought level with the mercury, as
can be done by shifting the scale, which is movable, in slides; the person
operating then blows through the tube D, the air passing into the
chamber A. The additional pressure of air and also the amount of air
blown in is indicated by the height to which the mercury rises in the
mercurial tube B, same being noted by the figures on the scale B². This
scale is graduated from a table calculated according to Marriott's law
of gases.
The spirometer shown in Figures 3 and 4 is a modification of that of
Figure 1, but in this case the chamber is in the form of a bellows or
expanding chamber, and is furnished with a pressure gauge and a
measuring apparatus. The bellows or expanding chamber may be
polygonal, circular, or square, and of known cubical capacity, say,
twenty-five cubic inches, and said chamber may be constructed of paper,
leather, cloth, india-rubber, or other flexible material, arranged in folds
similar to the sides of a concertina or accordion. The flexible sides are
fastened air-tight at each end to solid discs or plates a¹. To one end of
the bellows a pressure gauge B communicating with the interior of said
chamber is fitted. This gauge may be a glass tube partially filled with
mercury, water, or other fluid, or may be a metallic gauge, or an
aneroid barometer.
The measuring apparatus may be either a wood, ivory, or metallic rod,
divided either in ordinary degrees English, metrical, or otherwise, or
may be so divided as to indicate the cubical capacity of the vessel at
once by measuring the distance between the two ends. A more con-
venient apparatus. would be a tape, linen, or steel 6, one end of which is
fastened to one end of the chamber, as shown, and the other end rolled

page_text: round a reel (6¹) from which it is uncoiled by expanding the chamber.
The farther end of the chamber is provided with a nozzle and flexible
tube c, the opening of which into the spirometer is protected by a simple
valve d of oil, silk, or india-rubber, and also a relief valve f³, acted upon
by a projecting stud or lever g for the purpose of relieving the air from
the interior..
In order to use the spirometer shewn in Figures 3 and 4 the chamber a
is closed as far as possible, the ends being pressed together forcing the
air out by the relief valve f². The person operating then blows through
the flexible tube c whilst he or another person gradually draws the
bellows or chamber a open, keeping his eye upon the pressure gauge B
and regulating the pull so that a pressure is maintained throughout the
operation. When the person operating has completed his respiration he
or any person continues to draw until the gauge B stands at zero, and
then reads off the capacity of the chamber a by the attached flexible
scale, or by applying the scale divided into cubic inches. Such instru-
ment will require to be graduated experimentally by means of an
ordinary gas holder of known dimensions.
. For more convenient manipulation it may be desirable to place the
chamber a in a box or suitable slides, and separate the ends by means of
screws or cord and pulleys.
In some cases this form of spirometer may be used to ascertain the
pressure as well as the capacity. Assuming the chamber when collapsed
is made of twenty-five cubic inches capacity the chamber a is fixed by
thumbscrew, as, for instance, by a thumbscrew which may be then fixed a
immediately underneath the index, and the person operating blows into
the chamber and the pressure is indicated on the gauge B (such gauge
being similar to that shown in Figures 1 and 2).
If thought desirable the arrangements shown in the Drawings may be
combined, so that in place of the mercurial tube, shown in Figures 18
and 2, the collapsible arrangement, shown in Figure 3, may be con-
nected to the adaptor B'; and also in some instances the force pump,
shown in Figures 1 and 2, may be entirely dispensed with.
Having now particularly described and ascertained the nature of the
said Invention, and in what manner the same is to be performed or put 3
in practice, I hereby declare that I claim the herein designated Inven-

page_text: tion of "Improvements in the Spirometer," as hercin-before described
(and illustrated by the accompanying Drawings), whereby my instrument
is made so as to show not only the capacity of the lungs but alsó the
comparative strength of the chest, it being understood that I do not
limit myself to the use of, nor do I claim, the details of construction
herein described, except as constituents of my said Invention.
In witness whereof, I, the said Henry Charles Mayer, have hereunto
set my hand and seal, this Twenty-second day of July, in the
year of our Lord One thousand eight hundred and seventy-five.
HENRY CHARLES MAYER. (L.S.)
Witness,
T. MORGAN,
Secretary,
Inventors' Patent Right Association, Limited,
21, Cockspur Street, S.W.