IMPROVED APPARATUS FOR DRAWING THE CURVES KNOWN AS LISSAJOU'S CURVES
Year: 1880

page_text: LETTERS PATENT to Alexander Reid Molison, of Swansea, in the County of
Glamorgan, Science Teacher, for an Invention of "IMPROVED APPARATUS FOR
DRAWING THE CURVES KNOWN AS LISSAJOU'S CURVES."
PROVISIONAL SPECIFICATION left by the said Alexander Reid Molison at
the Office of the Commissioners of Patents on the 2nd August 1880.
ALEXANDER REID MOLISON, of Swansea, in the County of Glamorgan, Science
Teacher. "IMPROVED APPARATUS FOR DRAWING THE CURVES KNOWN AS
LISSAJOU'S CURVES."
The object of this Invention is to provide a simple, efficient, and portable
apparatus for drawing the acoustical figures or curves known as Lissajou's curves.
It consists of a box so arranged that when the sliding or draw lid is reversed
(that is, withdrawn from its place and replaced upside down), certain fittings which
are attached to the lid are brought to the top, and the box with lid then forms part
of the instrument when in use, and as a packing case when not in use.
The apparatus consists of two pendulums made or arranged to vibrate at right
angles to each other, of a pen holder and pen guided or governed by one, while a
small table for the paper or other material to be laid on on which the curve is
to be drawn is guided or governed by the other pendulum.
The pendulums consist of pieces formed in the shape of a T, made of wood or other
suitable material C (Fig. 1), resting on suitable bearings or points P, P, and having
knife edges E, E, projecting from their ends and entering eyes, both points and
eyes being the fittings spoken of as being attached to the underside of the lid.
A cord or string S passes round each of the T pieces, either through holes or in
notches, or is otherwise secured to the cross pieces. A weight W is suspended, and
the whole forms, when the T pieces are on their supports, pendulums of a triangular
form, two equal sides being of cord, and each being capable of freely vibrating
about an axis represented by a line drawn from the point of support to the knife
edge. One of the T pieces is furnished with an upright U (Fig. 2), on which is a
small table T, made so that its surface is a portion of the curved surface of a
cylinder of radius equal to the height of the table above its centre of motion, so
[Price 6d1

page_text: that when the table vibrates the pen will remain at right angles to the surface, if so
arranged, in one direction of vibration. This curvature also assists in the more
securely holding the paper or other material by the two elastic rings placed round
the curved surface of the table for that purpose E. The T is also furnished at R
(Figs. 1 & 3), with a reel turning tightly on a peg, to which reel the cord is attached,
so that by the reel the length of one pendulum may be regulated. The other
T piece is fitted with an upright V (Figs. 2 & 3), which carries a cross bar D,
Fig. 3, whose extremities are pointed and enter into holes made for them at h, h,
(Fig. 1) in the penholder, and thus the holder is permitted to move in a vertical
plane. The pen is held by a suitable arrangement at Q, and a bar carrying a
sliding weight X enables the pressure of the pen on the table to be regulated.
The apparatus, havingbeen put together, is placed on the corner of any table or
other support, the pendulums depending over the edge requiring no special stand
nor fixing, as from the arrangement, although heavy weights hang outside their
supports on adjacent sides, the centre of gravity of the whole falls within the area.
covered by the box, so that the apparatus so placed is stable and steady.
The points claimed by me are, the construction and arrangement of pendulums
in the aforesaid manner, for the aforesaid purpose, and for the arrangement and
combination of parts for the aforesaid purpose, viz., to provide a simple, portable,
and efficient apparatus for drawing Lissajou's curves.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Reid Molison in the Great Seal Patent Office on the 2ud
February 1881.
ALEXANDER REID MOLISON, of Swansea, in the County of Glamorgan, Science
Teacher. "IMPROVED APPARATUS FOR DRAWING THE CURVES KNOWN
LISSAJOU'S CURVES."
AS
The object of my Invention is to provide a simple, portable, and efficient
apparatus for drawing the acoustical figures or curves known as Lissajou's curves.
It consists of an oblong box so arranged that the lid (which is a sliding one) can
be reversed, that is, turned upside down in the box, and thus certain fittings
presently to be mentioned are brought to the top. The box and lid serve as part
of the instrument, and when not in use as a packing case.
Two pendulums are provided and so mounted that their arcs of vibration are at
right angles to each other, as is usual in instruments of the kind, and one part of
the novelty of my Invention consists in the peculiarity in the construction and
suspension of these pendulums for the purposes of this instrument.
pendulums govern or move, the one the pen, and the other the table on which
the paper or other material is placed on which the curve is to be traced, an
arrangement also common to similar instruments.
These
The pendulums consist of two pieces made of wood, metal, or other suitable
material of the form of a T, A, Figs. 1, 2, 3, resting on points B, B, which project
from the lid, and having also knife edges projecting from their ends and entering eyes
D, D, also fixed to the lid, the points and eyes being the fittings above alluded
to. Each piece thus forms a rocker, and is adjustable to vibrate freely, the
points being the downward bearings, while the eyes are the upward bearings.
A cord or string C, C, passes round each of the cross pieces of the rockers, either
through holes or in notches, or are otherwise suitably attached; W, W, shew
weights suspended by the cords, and in this way two triangular pendulums are
formed, which have the advantage of being easily packed away when not in use.
Both the T pieces or rockers are furnished with uprights, the one near the end F,
the other near the cross bar of penholder. On the upright near the end a small
table H is placed, whose surface is portion of a cylinder of the radius of the
length of the upright. Two bands of india rubber I, I, are passed round the
curve, and by this means hold the paper tightly on the table. This form of table
also enables the pen which it is to be used to remain at a constant angle on the
paper, undisturbed by the movement of the table. The upright on the other
Tpiece or that near the cross carries a cross bar J, J, Figs. 1 & 3, whose
extremities are pointed and enter into holes K, K, made for them in the penholder,
and thus the penholder is made to move in a vertical plane. A projecting bar L
carries a small sliding weight M to counterpoise portion of the weight of the pen
and holder, and to regulate the pressure of the pen on the material to be drawn
upon. The pen is attached at N by a suitable arrangement. On either of the two
rockers a peg O projects, on which a reel P stiffly turns, and to which reel the cord
is attached. By turning this reel the cord is wound or unwound, and the length of
the pendulum is regulated; the cord in this case passes over two projecting knobs or
buttons Q, Q.
It is obvious that various modifications could be carried out without departing
from the principle of the instrument.
In use the machine is placed on the corner of a table or other level or horizontal
support, and stability is secured by the arrangements mentioned.

page_text: Having now described my Invention, and the best mode known to me of
performing the same, I claim as novel and original,-
I. The method of constructing, suspending, and adjusting the pendulums,
substantially as described.
II. The improved form of table and method of preserving its relative position to
the pen, substantially as described.
III. The construction and method of regulating and adjusting the penholder,
substantially as described.
VI. The arrangement of box carrying and holding the apparatus, substantially as
described.
V. The general arrangement of apparatus, substantially as and for the purposes
hereinbefore described.
In witness whereof, I, the said Alexander Reid Molison, have hereunto set my
hand and seal, this Thirty first day of January, in the year of our Lord
1881.
ALEX³. REID MOLISON. (LS.)