A NEW DOUBLE CONCAVE BOILER, WITH A FLANCH FOR RAISING STEAM BY FIRE TO WORK ATMOSPHERE ENGINES FOR RAISING WATER, & OTHER PURPOSES, & BY MEANS WHEREOF SUCH ENGINES MAY BE WORKED AT MUCH LESS EXPENCE THAN THEY HAVE BEEN HERETOPORE
Year: 1748

page_text: STEPHENS AND HADLEY'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, THOMAS
STEPHENS, of the Parish of Saint James, in the Liberty of Westminster, in the
County of Middlesex, Ironmonger, sends greeting.
WHEREAS His present Majesty King George the Second, by Letters
Patent under the Great Seal of Great Britain, bearing date the Twelfth day
of July last past, reciting that Moses Hadley of the Parish of St. Martin in
the Fields, in the County of Middlesex, Engineer, and the said Thomas
Stephens, had, by their petition to His Majesty, represented that they had
lately invented "A NEW DOUBLE CONCAVE BOILER, WITH A FLANCH FOR RAISING
STEAM BY FIRE TO WORK ATMOSPHERE ENGINES FOR RAISING WATER, & OTHER
PURPOSES, & BY MEANS WHEREOF SUCH ENGINES MAY BE WORKED AT MUCH LESS
EXPENCE THAN THEY HAVE BEEN HERETOPORE," & praying His Majesty's Letters
Patent for the sole use thereof, His Majesty did thereby give & grant unto
the said Moses Hadley and Thomas Stephens, their executors, administrators,
& assigns, His especial licence, full power, sole priviledge and authority, to
make, use, exercise, & vend their said Invention within England, Wales, or
Berwick upon Tweed, to have, hold, exercise & enjoy the same for the term
of fourteen years from the date thereof; in which said Letters Patent is con-
tained a provisoe that if the said Moses Hadley-and Thomas Stephens, or one
of them, should not particularly describe and ascertain the nature of the said

page_text: Invention, and in what manner the same is to be performed, by an instru-
ment in writing under their hands and seals, or the hand and seal of one of
them, and cause the same to be inrolled in the High Court of Chancery
within four kalendar months next after the date of the said Letters Patent,
that then the said Letters Patent, and all advantages thereby granted, should
cease and become void.
NOW KNOW YE, that the said Thomas Stephens, in pursuance and per-
formance of the said proviso, doth hereby describe and ascertain, the nature of
the said Invention, & in what manner the same is to be performed, as follows,
that is to say:-
. .
.
The said boiler is made of copper or iron plates, hammered and riveted
together in the ordinary way, and of the ordinary form and make of the boilers
now in coñion use in atmosphere engines, and for the like purpose of boiling
water for raising steam by which those engines are worked, with the following
differences, that is to say: the bottom of the said new invented boiler is of
an uneven form or make, some parts thereof descending or projecting below
the other parts thereof in two troughs or hollows, the inward trough or hollow
forming a circle round the middle concave or open space, which concave or
open space is about three feet six inches diameter and three feet six inches in
depth, and which inward trough or hollow is about three feet six inches in
depth and one foot in breadth; and at about one foot distance from the said
inward trough or hollow there is another trough or hollow of about two feet in
depth and one foot in breadth, forming also a circle round the said inward
trough or hollow, the space or distance between the said inward and outward
troughs or hollows forming a second concave or open space of about one foot
in breadth for the fire to pass through from the middle concave or open place,
under which middle concave or open place the fire is placed; which said new
invented boiler, being set in a spiral form, admitts the fire (which passes through
each concave or hollow place) to play round and between the said troughs or
hollows, and also by the help of a flanch or elbow of about one foot in breadth,
that projects from the top of the said outward trough or hollow, there is an
open space between the said boiler and the brickwork for the fire to pass and
coniunicate with the outside of the lower part of the said boiler and flanch, by
which means the water contained in the said troughs or hollows and other
parts of the said new invented boiler, is heated by a considerable less quantity s
of fire, and also produces a greater quantity of steam than is produced by the
common boilers now in ordinary use; and such trough or hollows and concaves,
or open spaces in the bottom of the said new invented boiler, may be made of
greater or less width or depth, or more or fewer in number, according to the

page_text: igness of the engine to be worked by such boilers, & also with or without a
anch or elbow. And a plan or draft of the said new invented boiler, & the
banner of setting, is here-under made.
In witness whereof, the said Thomas Stephens hath hereunto set his
hand and seal, the Twenty-seventh day of August, in the twenty-
second year of the reign of our Sovereign Lord George the Second, by
the grace of God, of Great Britain, France, & Ireland, King, Defender
of the Faith, & so forth, and in the year of our Lord One thousand
seven hundred and forty-eight.
duly stamped) in the presence of
Josª SHARPE.
WILLIAM DIXON.
AND BE IT REMEMBERED, that on the Twenty-third day of September,
the aforesaid Thomas Stephens came before our Lord the King in His Chancery,
and acknowledged the aforesaid writing, and every thing therein contained
and specified, in form above said. And the said writing was stamped according
to the Act of Parliament made in the Sixth year of the reign of the late King
William and Queen Mary, & so forth.