A PHILOSOPHICAL FIRE ALARM, TO BE APPLIED TO HOUSES AND OTHER BUILDINGS
Year: 1787

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
STEDMAN, of Carey Street, in the Parish of Saint Clement Danes, in the
County of Middlesex, Perfumer, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of Great Britain, bearing date the
Nineteenth day of May, in the twenty-seventh year of His reign, give and
grant unto me, the said William Stedman, His especial licence that I, the
said William Stedman, during the term of years therein expressed, should
and lawfully might use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, my Invention of "A PHILOSOPHICAL FIRE
ALARM, TO BE APPLIED TO HOUSES AND OTHER BUILDINGS;" in which said Letters
Patent there is contained a proviso obliging me, the said William Stedman,
under my hand and seal, to cause a particular description of the nature
of my said Invention, and how the same is to be performed, to be enrolled
in His Majestie's High Court of Chancery within one calendar month after the
date of the said recited Letters Patent, 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
William Stedman, do hereby declare that my said Invention of a Philosophical
Fire Alarm is described in the Plan and description thereof now at the time
of acknowledgment thereof above annexed, and intended to be enrolled in His

page_text: Majestie's High Court of Chancery, and affixed to the Roll of Specifications
of Inventions in the proper office appointed for the purpose.
In witness whereof, I, the said William Stedman, have hereunto set iny
hand and seal, this Nineteenth day of June, One thousand seven
hundred and eighty-seven.
AND BE IT REMEMBERED, that on the Nineteenth day of June, in the
year of our Lord 1787, the aforesaid William Stedman came before our said
Lord the King in His Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stampt according to the
tenor of the Statutes made for that purpose.
Inrolled the Nineteenth day of June, in the year of our Lord One
thousand seven hundred and eighty-seven.

page_text: Fig: 1. represents part of a case or box with the apparatus ficed in it This bux is about one foot square and about two inches deep the top and the left side is made to turn back with hinges and may have
be preserved.
near the bulb or vessel A either at the front back or bottom that the
in a
easy
on
air may
act more,
immediately,
on the said bulb or vessel On the back are
a
in
-glazed door or be covered with anything provided an opening
fixt two holdfasts by which it is fastened against the wainscot or wall of the house or building where the instrument is
to be placed and should be hung. part least liable to be shook about two inches below the centre in the said box is fixed the ballance B.B. which may be made of any metal wood ivory & c but must be made as light as possible and turn very easy on its axis C.C. The length
of the left and of the ballance is about five inches and about half that length on the right which short end is made with a screw to screw on the wright D to ballance the other end loaded with the cup E The prop 0 should be near the axis to prevent the end on which the weight
is screwed from falling below the horizontal line The Cup E is in a conical shaft and is fixed so as to be easily taken off and put on again to the ballance one of the spring sockets which holds the bulb fast at P serves also for a prop to the ballance when it falls by thes
weight of the drop at the distance of about 1/8 of an inch perpendicular over the centre of the axis C fix a small peg F of about p inch long in an horizontal position and parralel with the axis of the said ballance. This small peg F supports the extreme end of
the horizontal side of the right angle G. G. the perpendicular side of which is charged with the weight II. This right angle turns upon its axis K. K. which axis is placed horizontal and paralel with the axis of the ballance B. but is placed) a little higher than the
Peg. F. the perpendicular side of the right angle and weight being perpendicular the wright of the horizontal side will fall when disengaged from the peg F. The horizontal side should be about 5 inches long and the perpendicular a l'ttle shorter se as not to touch the Peg.
- its axis and must project far enough from the back of the box or case thai in falling it may clear the ballance. In the side of the case perpendicular under the right angle is a slit I cut through the Board that the horizontal
falling.
This angle must move
free and.
side may pass through it and the wright in falling describe half a circle On the same side in the upper part a piece of wood M is fixed that prevents the weight for falling on the wrong side of the perpendicular line. The horizontal side of the right angle must be fixed inf
such a position on the little peg of the ballance that its pressure must be in a perpendicular and direct line to the centre of the axis of the ballance which otherwise would loose its equilibrium and it must also be short enough upon the peg that
by a small motion of the ballance it may be disengaged from it. On the perpendicular side under the weight is the pulling string N by which the alarm is set. agoing.
This string is kept so slack that it is not pulled till the wright I in falling has described or formed an angle of about 60 degrees On the opposite side of the case is fixed with two spring sockets the bulb or vessel with a tube which may be of any shape & size as occasion may requires
which should be filled with mercury but will act in a les powerful degree with spirits of wine or any other fluid. If it is to be used with mercury it should be large enough to contain about 8 or 10 ounces if it be used with other fluids it should be larger The tube is about 7 inches long and the
diameter of the bore is about o
one tenth of an inch the top of this tube is cut off slanted and a notch is filed under at the beginning of the slope which allows the top of the conducting tube Q to come quite close under the hole at which a small perpendicular nick is also filed The use is to
conduct the fluid drops into the conducting tube Q and into the cup E the conducting tube is about 3 inches long and may be made of glass tin or any other material and is fixed at a proper heighth with a spring socket above the cup E tather nearer to that side of the
Cup towards the axis of the ballance for the purpose that (when the ballance is down and thereby the perpendicular line over the cup bring nearer the centre) if there should continue to fall more drops they might fall into the cup just above the tube. A fix the spring socket.
R which is to keep the regulator S at any heighth required The Regulator S may be made of ivory. bone or any other matter that has no affinity with mercury and should be half the size of the bore that by pushing it down and pulling it up the fluid may rise and fall the
same space a scale of degrees must be marked on a plate or on the board at the back of the Regulator The Regulator must be set to the degrees by a Thermometer to that the fluid may be set to flow out at any degree of heat required. Note the lower the Regulator is in the
tube the sooner the fluid will run out at the top of the tube and fall by drops through the conducting tube in the Cup & The velocity of the fall of the drops joined to their wright in the Cup causes the ballance B to fall on this side together with the peo F. which being removeds
from under the horizontal side of the right angle the weight I falls down describing the circumference of a circle in course of which (when it is about 60 degrees / it pulls the shing № by which the alarm is set agoing The Alarm may be the same as in common or in some
near or in any remote place from this machine the communication of which to the string N is effected by cranks V as in House Bells and therefore neither of these need further description The above is formed upon a particular scale but the s
larger and
I may be placed
are observed and followed Fig 2nd instead of the right angle and weight the feather spring I can be used with the lever V one end of the spring bring fastened to the side of the box the other end when bent close
effect will be produced upon many others provided the proper proportions.
heighth with the peg F of the ballance b the lever I must be fixed to move easily on the centre or axis V which must be placed a little higher than the top of the spring so that the said spring may
is nearly at the same.
clear it when it flies off therefore the short ends
of the lever must be bent down so as to reach the top of the spring at W the end of the spring should be a little bent so that its pressure shall bear exactly on the axis of the lever I the left arm of the lever is so far extended as to lie on the peg F of the ballance and is to be just heavy
enough to fall upon the prop I when the peg is removed and thereby disengage the end of the spring I which in flying of pulls the string N and set the alarm agoing The thing I is fastened to the spring at X and passes through the side of the Box to pull the cranks
Xt as before described Fig 3rd the ballance may be made to fall different ways as follows. Fix the bulb A perpendicular about three inches from the conducting tube a little above the two tubes fix the ballance B.B. at the one end perpendicular over, the tube of the bulb-
A suspend by a thread the Regulator S made of ivory bone or other material that has no affinity with mercury and is to go easy in the hole of the tube at the other end is made a cavity the extremity of which turns a little upwards and has then a hole in it at C in the
lowest part of the cavity put the globular wright D which is small enough to pass through the hole C the ballance must be hung so that it is in equilibrium when charged with the Regulator S and the weight D when the fluid rises in the tube to the Regulator it begins
to support the Regulator and the equilibrium of the ballance B being destroyed the end C falls and the wright Drolls through the hole and through the conducting tube 9 where it produces the same effect as the fall of the drops before mentioned Fig 4th To make the Alarm go off
at any degree colder as well as hotter fix two bulbs A and B with their tubes C and D parralel and perpendicular place B.D. unda one end of the balance at which is suspended the regulator S'making equilibrium with the wright D at the ballance BB to the same effect as described in
Fig: 3 and place A. C. under the little knob fixed in the ballance at I Let the Regulator R go down in the tube C till it rest on the fluid and fasten the string slack as the number of degrees of cold you desire the alarm to go off the scale of degrees is marked behind the tube whene
the liquid contracted by the cold is sunk under the degree required the Regulator R pulls the string and by its weight destroys the equilibrium of the ballance B.B. and causes this end to fall and the weight D to roll and fall in the Cup E as in the former. The bulb or vessel with
two tubes B and C as in Fig 2 can be used both tubes are parralel to each other and placed perpendicular The regulating tube B is about 4 inches long and the bore or hole about 1/8th of an inch the bent tube C is about 8 inches long and its end is bent downwards and in a position
that the fluid may run out of it with certainty into the conducting tube Q and into the cup Es the bore of the bent tube is 1/16% of one inch in the end of the short tube put the stopper R through which passes the Regulator S about the same size as the hole of the small tube and is
regulated the same as the inclined tube Fig 1 The Stopper and Regulator must fit so close as to prevent any of the fluid from coming out of this end any metallic or other substance which is capable of sufficient degrees of expansion and contraction may be used instead of
fluid and bulbs described by the letters A and B In cases where it is required to immerse the bulb in a copper boiler or other vessel containing liquid the bulb with its tube may be brought without the box at the bottom or sides or any convenient part and the tube may by
made of any length and be bent into any shape proper to suit the vessel in which it is to be immersed It is requisite that the bulb and tube if it is made of glass should be lodged in a wire case or. anything that will prevent it from being broke and will give admission to
cases
Clocks.
same