AN INSTRUMENT FOR THE GENERA- TION OF FIRE AND VARIOUS PURPOSES IN CHYMICAL AND EXPERIMENTAL OPERATIONS
Year: 1811

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MICHAEL
LOGAN, of Paradise Street, Rotherhithe, in the County of Surry, Engineer,
send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Ninth day of September,
in the fifty-first year of His reign, give and grant unto me, the said Michael
Logan, my exors, adññiors, and assigns, His especial licence, full power, sole
privilege and authority, that I, the said Michael Logan, my exors, admors,
and assigns, during the term of years therein mentioned, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "AN INSTRUMENT FOR THE GENERA-
TION OF FIRE AND VARIOUS PURPOSES IN CHYMICAL AND EXPERIMENTAL OPERATIONS;"
in which said Letters Patent there is contained a proviso that if I, the said
Michael Logan, shall not particularly describe and ascertain the nature of my
said Invention, and in what manner the same is to be performed, by an instru-
ment in writing under my hand and seal, and cause the same to be inrolled
in His Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said Letters Patent, that then the said
Letters Patent, and all liberties and advantages whatsoever thereby granted,
shall utterly cease, determine, and become void, as in and by the same,
relation being thereunto had, may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Michael Logan, do hereby declare that my said Invention of the sceptre, a
martial instrument constructed for the instantaneous discharge of artillery,

page_text: either in military or naval service, is described and ascertained in manner
and form following (that is to say):
-
This Invention, as an instrument adapted to the operations of war, neces-
sarily consists of such parts in construction the least in number as are the
least liable to be put out of order, and the most certain of producing and
continuing its effects. These principles being the objects of this Patent I
have here only to explain the nature and plan of the instrument according as
it is applied either to field, fort, or naval service, by so plain a description as
to render any delineation of it unnecessary to an accurate or skilful workman.
The military scepter is therefore by mechanic combination formed by a staff
made either of wood or metal, solid or hollow, with a tube and guard fixed
on the end of it. For field and fort service the length of this instrument I
have found most convenient in practice to be from three feet to 3.5 feet, and
its diameter from 1.5 inch at the but or handle, to 1.25 inch at the shoulder
where the tube is brought on, the tube being an uniform cylinder from 7 to
9 inches in length, of 1 inch internal diameter, which may be either more or
less at pleasure, but not less than of an inch thick, unless it be the external
.cover or case of a glass tube contained in the inside of it; the end of this
tube terminates in the form of an half sphere, half an inch thick of metal,
with an orifice about a quarter of an inch diameter, through which the instru-
ment is charged, and into which is screwed a stopper air-tight, with a sphric
head and collar; as this instrument when applied to the discharge of artillery
is presented in an horizontal position to the vent parallel to the gun's axis,
with its rest placed on the breech ring of the ordnance, the guard which
covers the vent plug of the sceptre is placed and fixed close up to the circle
or base of the half sphere on the upper side of the tube, and extending
towards the handle about 3.5 inches on the tube; this guard is formed by
two parallel segments or plates of a circle about an inch deep in the sagetta
or diameter, or about half an inch wide or apart, and covered conformable
to the arch of the segment with a plate so as to protect the vent plug lever
and spring; the fulcrum of the lever is placed at a due distance from the
head of the vent plug, so as to admit of its being raised with ease by the
lever about one quarter of an inch, and which is instantly depressed again
when the cause is removed by the power of the spring bearing on the head
or collar of the plug; the spring made use of may be either spiral and bear-
ing down upon the head from the guard, or straight and laid parallel to the
tube, with its end bent and fixed under the collar of the end stopple; the vent
plug being a perfect frustum of a cone in this form of the sceptre, about two
inches and an half in length and tapering from 4 lines diameter at the head

page_text: to one line diameter at the point of contact; it is placed perpendicular to the
axis of the tube, and fitting perfectly air-tight the upper and lower, orifices of
the tube itself; and also those of the cone fixed on the lower side of the
sceptre; it therefore becomes the conservator and regulator in the operations
of this instrument. Under the collar of the vent plug is the air vent, close
to the upper orifice, so that when the plug is raised the pressure of the
atmosphere instantly takes place, and gives one drop or sphere th of an
inch diameter of the fluid contained in the tube of the sceptre for each
stroke or jet of the regulator. From the tail of the lever is extended through
a small grove the wire of communication to the trigger in the handle, which
is let in below the cylindrical surface of the staff so as to prevent and avoid
accident; the form of this trigger being so simple and common in construction
as to require no description from me to any operative mechanic.
Having thus explained the construction and form of the military sceptre
the same principles applied to naval service seem to require some other modi-
fication of the instrument as employed in a discharge of marine artillery ;
therefore, should this change be necessary, I have made the marine sceptre
with a shorter staff for more convenience; and in place of a cylindrical tube
I have made use of a double cone, the common axis of which is placed per-
pendicular to that of the staff and its common base being nearly in the plane
of the staff's axis; the lower cone by construction serves as the reservoir, and
the upper one as the guard of the instrument, with the axis of each cone
equal to the diameter of their common base, which in the instrument I have
made is about 2.5 inches diameter.
I have here therefore finally to remark, that I do not confine myself to this
form of the head of the marine sceptre, whether it be a cone, tube, sphere, or
conoid, eliptical, parobolical, hyperbolical, or any other form or figure whatsoever
that can be described either mechanically or mathematical; nor do I confine
myself to any material substance whereof the same may be constructed, which
will contain and withstand the action of the fluids, either pure spirit or acids,
whether simple or compound, which generate or produce the effect of inflama-
bility or fire, being brought in contact with pyrotechnick compositions. Of
these compositions their commixtures are so various as would require a
volume to describe them, and consequently cannot therefore become the
subject of specification here, many of which are so well known by fire-
workers, that almost every linkboy or sweeper knows how to generate fire;
but to apply the materials above alluded to to millitary operations it is indis-
pensibly necessary that the instruments employed should be adapted by con-
struction the most perfect to the purposes of war, so as completely to exclude

page_text: all humidity and absorptions of the atmosphere, particularly when the acids
are employed, or when the phosphoric or pyrophoric substances are used.
The sceptre, therefore, that with one charge to be obtained in one minute,
and when in practice ought by construction to continue so as to produce
the discharge of 22512 rounds of cannon shot, is an instrument worthy of
attention and fit for warlike service.
In witness whereof I, the said Michael Logan, have hereunto set my
hand and seal, the Seventh day of March, in the year of our Lord
Inrolled the Seventh day of March, in the year of our Lord One thousand
eight hundred and twelve.