THE MANUFACTURE OF AN INSTRUMENT TO FACILITATE THE PRACTICE OF THE DRUM
Year: 1861

page_text: LETTERS PATENT to John Christopher Caesar Azémar, of 40, Mark Lane,
in the City of London, for the Invention of "THE MANUFACTURE OF AN
INSTRUMENT TO FACILITATE THE PRACTICE OF THE DRUM."
Sealed the 21st February 1862, and dated the 27th August 1861.
PROVISIONAL SPECIFICATION left by the said John Christopher Caesar
Azémar at the Office of the Commissioners of Patents, with his
Petition, on the 27th August 1861.
I, JOHN CHRISTOPHER CAESAR AZÉMAR, of 40, Mark Lane, in the City of
London, do hereby declare the nature of the said Invention for "THE MANU-
FACTURE OF AN INSTRUMENT TO FACILITATE THE PRACTICE OF THE DRUM," to be
as follows:-
My object is to make an instrument by which the beating of the drum may.
be practised without noise, the effect of the strokes being conveyed through
the medium of feeling mostly instead of through the ear.
I take two round plates of mahogany or other wood not vibrating to sound,
and place between the plates india-rubber or cloth, and fix the two plates
together cross-grained by glue or otherwise. On the upper of the two plates
I fix a sheet of india-rubber of sufficient thickness to give the proper recoil of
a drum; the lower plate is covered with cloth. I fix the whole on the leg of
the person practising by means of a strap passed through two parallel pieces of
wood, which are fixed in the instrument. The instrument is encircled in a

page_text: band of leather or other similar material. The sticks used are the ordinary
drumsticks.
In order to get a slight sound from the instrument, I fix the two plates
together by screws, which separate and tigliten the two plates at will. The
band of leather is theu fixed either in the top or bottom plato, so as to enclose
the space between the plates, and is perforated with holes. The upper plate
must then be of wood vibrating to sound.
The instrument may-be fixed on the ordinary drum to enable the learner to
march and countermarch while practising.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Christopher Caesar Azémar in the Great Seal Patent
Office on the 24th February 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CHRISTOPHER CÆSAR AZÉMAñ, of 40, Mark Laue, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of August, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Hler
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
snid John Christopher Cesar Azémar, Her special licence that I, the
snid John Christopher. Cæsar Azémar, my executors, administrators, and
assigus, or such others as I, the said Jolin Christopher Casar Azémar, 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, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "THE MANUFACTURE OF AN INSTRUMENT TO FACILI
TATE THE PRACTISE OF THE DRUM," upon the condition (amongst others) that I,
the said John Christopher Cesar Azémar, my executors or administrators,
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 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 John Christopher Caesar Azémar,
do hereby declare the nature of my said Invention, and in what manner

page_text: the same is to be performed, to be particularly described and ascertained in
and by the following statement:-
The annexed plate No. 1 shows my instrument. The best size is about
twelve inches diameter.
Figure 1. The upper side of the instrument "A" is a surface of vulcanized
india-rubber; A 1, a hoop of wood round the same.
Figure 2.-B shows the under, side; c, c 1, are two parallel bars of wood,
with a cut in each of them, as shown in Figure. 2 a, for the purpose of holding
a strap to fasten round the leg, and of fitting on the left leg properly. Fisa
piece of iron fastened to, the wood c 1, and shown shut for convenience sake,
and secured by the button. G. The said piece F is intended when open, as in
Fig. 4, to hold-the instrument in the proper position by resting against the
inside of the left leg.
.
.
Figure 8 shows the side view of the instrument facing the two parallels c, c 1.
a shows the wooden hoop.
Figure 4 represents another side view, with the longi dinal view of one of
the parallels. Figure 4 also shows the leg piece D open, and its proper
position. A shows the metal button holding the leg piece D when not
in use.
Figure 5 is a section of the instrument cut through the diameter. A is the
india-rubber, which is glued on two boards B and D, between which is glued
a piece of stuff of woollen or other cloth; the grain of the wood of said
boards B and D being put crossways in relation to each other, as shown in
Figure 6, B and D. I obtain the desirable elasticity of the instrument,
I find that the best thickness of the rubber I can obtain is about five-sixteenth
inch, but it depends entirely on the elasticity of the rubber obtained. I also
find that to combine lightness with absence of sound, it is preferable to
have two boards constructed as described, and separated by some woollen stuff,
choosing the wood combining as much as possible hardness with lightness, and
as much as possible not conveying sound. This mode of construction tends
also to give a firmer support to the rubber, and thereby materially increasing
its elasticity. The bottom of the instrument, as well as the parallel bars,
I cover with cloth to subdue the sound, still more to give a better hold on the
leg, and to give a neater appearance, but it is not material to the Invention,
neither are the double boards, as in Figure 6, where a slight increase of sound
is not objectionable. The instrument being strapped round the left leg, so
that the iron tongue D, Figure 4, rests against the inside of the leg and
against the knee, it is necessary when standing to raise the said leg by the
help of a footstool or other, means to have it conveniently placed. Sitting, the

page_text: best posture is to bend the left leg under, and stretch the right one forward,
resting the right side of the instrument on the right leg, Any ordinary well
balanced drum sticks can be used. In this plate the scalo is four inches to
the foot.
A modification of the ins
instrument producing subdued sound is shewn in
Plate 2, as stated below; the sound is subdued by shutting the plate j,
Figure 2, over the intersection of plate i. It can be further subdued and the
tono modulated by screwing up the table w, Figure 4, towards the vellum, and
by bringing it in close contact with the vellum, absence of sound for practise is
obtained. Care must be taken to stretch the vellum by means of tho scrow,
ns in the ordinary drum, before using the instrument at all.
In Plate 2, Figure 1 shows a top plan. a is an ordinary vellum drum
head; b, a wooden hoop; c, the nuts for tightening the drum head, as
customary; d, a nut and hook to tighten the snare fixed on button E, E;
f, metal hook, to hang the drum to a strap passed round the waist; g, a
button to fix the music holder.
Figure 2 shows the bottom plan. c, d, f, g, explained in Fig. 1; h, a brass
hoop, over which the vellum is drawn, as in the ordinary druni; i, a wooden
frame, consisting of six open compartinents, fastened by screws to ring.h, and
further explained in Figure 5; j, a metal plate with six open compartments,
as explained in Figure 6; k, a wooden ring screwing plate j'against frame i,
allowing the same to open or shut the compartments by means of the button 1,
as in the common ventilator, so that the sound is increased or diminished at
will; m, wooden screw, working in ring k, further explained in Figure.4; n, a
handle to screw or unscrew said ring m; o, o, two metal pieces, secured to
ring by metal piece p, moving at will by means of nut q, further explained
in Figure 3, laid flat when not in use for convenience sake.
h
Figure 8 is a side view. b, c, d, e, f, explained in Figure 1.; h, k, l, n,
explained in Figure 2. o, o, leg pieces, shown shut in Figure 2; p, metal
piece, holding the same to ring h; 9, a nut to tighten the same when placed
in the required position; 7, a strap to connect pieces o, o, together; s. the
hoop to which the vellum is secured, as in the ordinary drum; t, the snare
secured to hook and nut d, to be tightened at will, something similar to tho
ordinary drum, with this exception, that the snare is squeezed between tho
vellum and the brass hoop instend of the vellum being squeezed between the
snare and the brass hoop, as is the case in the common drum.
.
Figure 4 is a vertical section through the centre, a, b, c, explained
Figure 1. h, i, j, k, l, n, explained Figure 2. s explained in Figure 3.
ma wooden screw working in a female screw cut in ring a, u, a sheet of

page_text: vulcanized india-rubber from about a quarter to about half an inch thick,
according to the elasticity of the rubber used, glued on, plato v, said plate
made of two or more pieces of veneer for strength and resistance's sake, plate v
being fastened to screw m by means of screw w or otherwise. Plate v can be
made of metal or a single plate, of wood where lightness and durability is not
an object; y, screws to fasten wooden frame i to metal ring h.
Figure 5 shews the construction of the wooden frame.i. is the female
screw already mentioned in Figure 4, into the outer circumference of which
the flanges i are mortised. The number immaterial, but the surface of each to
be equal to the space between them. y are the screws, as shewn in Figure 4,
by which the whole is fixed firmly; his explained in Figure 2. This frame i
is lined with cloth to prevent j, Figure 6, rattling against it.
Figure 6 is the revolving plate j, formerly mentioned, made of tin plate,
metal, or wood, having for its object to close at will the intermediate space
between the flanges; is the button to work the same.
Plate 2 is made on the scale of three inches to the foot..
In witness whereof, I, the said John Christopher Caesar Azémar, have
hereunto, set my hand and seal, the Twentieth day of February, in
the year of our Lord One thousand eight hundred and sixty-two.