IMPROVEMENTS IN THE CONSTRUCTION OF AUDIBLE ALARM
Year: 1875

page_text: LETTERS PATENT to Nathaniel John Holmes, of The Hall, Primrose
Hill Road, Regent's Park, London, Middlesex, Gentleman, for the
Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF AUDIBLE ALARM
Sealed the 6th December 1875, and dated the 10th August 1875.
PROVISIONAL SPECIFICATION left by the said Nathaniel John
Holmes at the Office of the Commissioners of Patents, with his
Petition, on the 10th August 1875.
I, NATHANIEL JOHN HOLMES, of The Hall, Primrose Hill Road,
Regent's Park, London, Middlesex, Gentleman, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF
AUDIBLE ALARM SIGNALS FOR MARINE AND OTHER PURPOSES," to be as
follows:
My improvements consist in the manner of constructing audible alarm
signals, such as fog horns or trumpets, to produce a maximum amount
of sound or noise with simple mechanical and accoustical arrangement
of parts.

page_text: By means of my improved method of construction I am able to form
what I designate a compound or mixture reed fog alarm. In principle
this compound or mixture reed fog alarm may be described as consisting
of two or more separate and independent "reed" or sound vibrators, so
constructed and disposed as to form when acted upon by a current of
compressed air the sound producers in connection with one or more
trumpet-shaped tubes in the manner to be hereafter described.
The sound producing power of the compound reed or mixture fog
alarum is determined by the relative proportions of the vibratory reeds
and the diameter and length of the trumpet-shaped tube or tubes
according to accoustical laws well known in connection with the pressure
of the air driven through the vibratory reeds or mouth-pieces.
One or more forms of the compound or mixture reed fog alarm, which
I find may be successfully employed, may be described to be more or
less as follows:-Two metal "reed vibrators" constructed with broad
tongues after the principle of the large pedal reed vibrator of an organ-are
placed back to back, the pitch of one of the reeds being adjusted to
sound either unison, fifth, or octave, or other musical interval best
calculated to produce in combination a tone or compound sound of the
greatest carrying capacity. These vibratory reeds, two or more combined
together as the mouth-piece, may be placed at the extremity of an
ordinary trumpet-shaped tube with a bell-shaped mouth-piece to spread
the sound vibrations. The compound or mixture reeds are set in
vibration by forcing air through them from a portable wind generator
in connection with them. This generator may either form an integral
part of the trumpet and reed arrangement in the manner hereafter to be
described, or may be a separate machine actuated by the foot or other
suitable mechanical motor having tube connections to convey the com-
pressed air to the reeds. '
The arrangement of the compound or mixture reeds may be so varied
as that each reed, be it two or more, shall vibrate into its special trumpet
tube of suitable dimensions and length, the several tubes being arranged,
the smaller round the larger, in a convenient form, or the several vibratory
reeds may speak into one common trumpet tube; in either case the
reeds are supplied with compressed air by any of the well-known
mechanical appliances for such purpose, such as the syringe condensing
pump, the ordinary cylinder and plunger, or other arrangement. In

page_text: constructing this wind producing arrangement it may either be so con-
trived that the compound reed vibrators and trumpet tube arrangements
shall form an external addition to the wind pump and connections, or
the compound mixture reeds with the necessary trumpet tubes may be
so arranged as to form an internal part of the wind producing machine.
Such arrangement either as an external pump or otherwise may be
modified, as is found to be most portable and convenient for the purposes
required in connection with the compound or mixture reed arrangement
of vibrators.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Nathaniel John Holmes in the Great Seal Patent
Office on the 9th February 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, NATHANIEL
JOHN HOLMES, of The Hall, Primrose Hill Road, Regent's Park, London,
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of August, in the year
of our Lord One thousand eight hundred and seventy-five, in the
fortieth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give, and grant unto me, the said Nathaniel John Holmes,
Her special licence that I, the said Nathaniel John Holmes, my
executors, administrators, and assigns, or such others as I, the said
Nathaniel John Holmes, 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 King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF AUDIBLE
ALARM SIGNALS FOR MARINE AND OTHER PURPOSES," upon the condition
(amongst others) that I, the said Nathaniel John Holmes, 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

page_text: Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Nathaniel John Holmes, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
-
My improvements consist in the manner of constructing audible alarm
signals, such as fog horns or trumpets, to produce a maximum amount
of sound or noise with simple mechanical and accoustical arangement
of parts.
By means of my improved method of construction I am able to form
what I designate a compound or mixture recd fog alarm. In principle
this compound or mixture reed fog alarm may be described as consisting
of two or more separate and independent "reed" or sound vibrators, so
constructed and disposed as to form when acted upon by a current of
compressed air the sound producing parts in connection with one or
more trumpet-shaped tubes in the manner to be hereafter described.
The sound producing power of the compound or mixture reed fog
alarm is determined by the relative proportions of the vibratory reeds
and the diameter of the trumpet-shaped tube or tubes, according to
length and acoustical laws well known in connection with the pressure
of the air driven through the vibratory reeds or mouth-piece.
One or more forms of the compound or mixture reed fog alarm, which
I find may be successfully employed, may be described to be more or
less as follows:-Two metal " "reed vibrators" constructed with broad
tongues after the principle of the large pedal reed vibrator of an organ
are placed back to back, the pitch of the reeds being adjusted to sound
either the same unison, fifth, octave, or other musical interval best
calculated to produce in combination a tone or compound sound of the
greatest carrying capacity. These vibratory reeds, two or more combined
together, as the mouth-piece may be placed at the extremity of an
ordinary trumpet-shaped tube with a bell-shaped mouth-piece to spread
the sound vibrations. This compound or mixture reed arrangement is
set in vibration by forcing air through them from a portable wind
generator in connection with them. This generator may either form an
integral part of the trumpet and reed arrangement in the manner here-
after to be described, or may be a separate machine actuated by the

page_text: foot or other suitable mechanical motor having tube connections to
convey the compressed air to the reeds.
The arrangement of the compound or mixture reeds may be so varied
as that each reed, be it two or more, shall vibrate into its special trumpet
tube of suitable dimensions and length, the several tubes being arranged
or grouped together in a convenient form, or the several vibratory reeds
may speak into one common trumpet tube; in either case the compound
reed is supplied with compressed air by any of the well-known mechanical
appliances for such purpose, such as the syringe condensing pump, tlie
ordinary cylinder and plunger, or other arrangement. In constructing
this wind producing arrangement it may be either so contrived that the
compound reed vibrators, and trumpet tube arrangements shall form an
external addition to the wind pump and connections, or the compound
mixture reeds with the necessary trumpet tube or tubes may be so
arranged as to form an internal part of the wind producing machine. Such
arrangement either as an external pump or otherwise may be modified as
is found to be most portable and convenient for the purposes required in
connection with the compound or mixturé reed arrangement of vibrators.
Another novel form of the compound recd arrangement of vibrators
which I use is the employment of two similar vibrating reed tongues
placed together, so as to vibrate as a split reed in unison upon a current
of air being driven into the mouth-piece. This compound or
"split"
reed arrangement produces a most powerful tone with a very small
expenditure of air, and likewise posseses prompt speech.
When I require to produce a more continuous sound, so as to give
speech to the fog alarm, both at the time of the exit of the compressed
air, and also upon the inhalation of the air into the mechanical bellows, I
employ a compound arrangement of two or more free reeds or vibrators,
which are so adjusted by any of the methods well known as to give
speech upon the forcing of a current of air through them in either
direction. This compound free reed arrangement may be employed in
connection with a trumpet tube or tubes with a bell-mouth, as before
described, to ensure carrying capacity, and the vibration of a large
column of air.
I claim as new the employment of the compound reed arrangement
consisting of two or more vibratory reeds, so placed and combined
together as to vibrate into the same tube or into distinct tubes at the

page_text: same time by the action of compressed air, as above described, for the
purpose of by their combined vibration in unison or other musical pitch
of producing a powerful sound.
I also claim for audible alarm signals the employment of a compound
arrangement of the "free reed" to produce a more continuous sound,
which I may designate as a double-action sound produced by the passage
of the air through the reed arrangement in either direction, as above
described, for producing audible alarm signals.
Witness to the above Signature,
ALFRED TURNER,
8, G. Winchester Street,
London.
NATH. J. HOLMES.