IMPROVE- MENTS IN STEAM ENGINES
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
CRAIG, of Edinburgh, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing
date at Westminster, the Twenty-fifth day of November, in the fifth year
of His reign, did, for Himself, His heirs and successors, give and grant
unto me, the said Alexander Craig, His especial licence, full power, sole
privilege and authority, that I, .the said Alexander Craig, my exors, adñiors,
and assigns, or such others as I, the said Alexander Craig, my exors,
adiiors, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, the Invention of "IMPROVE-
MENTS IN STEAM ENGINES," communicated to me by a certain Foreigner residing
abroad; in which said Letters Patent is contained a proviso that I, the said
Alexander Craig, shall cause a particular description of the nature of the
said Invention, and in what manner the same is to be performed, to be
inrolled in His said Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Alexander Craig, do hereby declare the nature of the said Invention,
and the manner in which the same is to be carried into effect, are fully
described and ascertained in and by the following description thereof, reference
being had to the Drawing hereunto annexed, and to the figures and letters
inarked thereon, that is to say:-
The Invention communicated to me from abroad relates to that description
of steam engines which are known by the name of Rotatory Steam Engines.
DESCRIPTION OF THE DRAWING.
Figure 1 represents a side view of the engine, the revolving arm not
being visible, as they are enclosed in a circular case, to be hereafter
described. A is a steam tube connected with boiler and forming a steam-
tight joint in the box B where it opens into the shaft C, which is made
hollow to the required depth; D is the edge or periphery of a case or drum,
within which the arms from which the steam is to issue revolve; E, E, are
braces which may be attached to the case or drum, and at their junction
support a socket containing a centre pin or screw F, against which the
shaft C is to run; G is a tube through which the steam passing into the
case from the revolving arms is allowed to escape; a portion of this steam is
employed to heat the water by which the boiler is to be supplied; H is a
wheel, upon which the shaft C, a strap from which may be employed to drive
machinery (where the same parts occur in the other Figures in the Drawing
they are represented by the same letters). Figure 2 shows the flat side of
the drum or case, the arms or braces E, E, the wheel H, and the manner in
which straps or other gearing may be carried from one wheel to another.
Figure 3 is the opposite side of the drum or case. I, I, in Figure 4, shows
the flat sides of the revolving hollow arms, and J, J, Figure 5, is an edge
view of the same. In Figure 4 one side of the case is supposed to be
removed, and in Figure 5 the whole case; at K, K, openings are made in the
narrow edges of the arms in directions opposite to each other to allow of the
escape of the steam introduced into them through the shaft C, with the
hollow of which they communicate. The width of the arms (in the Drawing
annexed) at the centre is about six inches, and at the ends about one and a
half inches near the centre, and about three fourths of an inch near the end.
The size of the holes through which the steam escapes is about one quarter
by one eighth of an inch; the holes are so perforated that the steam shall
issue at right angles with the shaft. This engine is found to act with great
power. L, L, are parts of stuffing boxes employed to prevent the escape of

page_text: steam in a manner well known to machinists. It will be found to be a point
of great importance to give such a form to the revolving arms as shall subject
them to the least possible resistance from the air; therefore, instead of making
them in the form of round tubes, which has been heretofore done, I give to
them the form which results from making each half of the arm a segment of
a large circle, so that when the two halves are united the edges of the tube
presents acute angles; the tubes, however, may be made eliptical or oval,
and the same end will be in a great measure attained. I use any number
of such arms on the same shaft as may be found best adapted to the purpose.
What I claim as the Invention communicated to me as aforesaid, is simply
giving the oblate or flat form to the revolving arms, and enclosing them in a
case, so that in proportion to their capacity they shall experience much less
resistance from the air than that to which they have been heretofore subjected,
thereby obtaining a greatly increased power.
Having thus described the nature of and the features of novelty claimed
under this present Patent, I would remark that it will be evident that these
steam engines, in addition to other uses, will be particularly applicable to
locomotive purposes, in consequence of their lightness.
In witness whereof, I, the said Alexander Craig, have hereunto set my
hand and seal, this Sixteenth day of May, in the year of our Lord
One thousand eight hundred and thirty-five.
This is the Specification referred to in the athdavit of William Carpmael,
sworn before me, the 25th day of, 1835.
Before ine,
Jas. Thowen.
William Carpinael, of Lincoln's Inn, maketh oath that he hath received the
Specification of Alex Craig for enrolment. And this deponent further saith,
that he is well acquainted with the handwriting of the said Alexander Craig,
and that the signature on such Specification is in his handwriting. And
this deponent further saith, that he is informed, and verily believes, that the
William Carpinael, of Lincoln's Inn, maketh oath that he hath received the
Specification of Alex Craig for enrolment. And this deponent further saith,
that he is well acquainted with the handwriting of the said Alexander Craig,
and that the signature on such Specification is in his handwriting. And
this deponent further saith, that he is informed, and verily believes, that the

page_text: said Specification was acknowledged before John Cuningham, and that the
signature to such acknowledgement is in the handwriting of the said John
Cuningham, and that he was a Justice of the Peace at the time of receiving
such acknowledgement.