[Footnote 1: _The Eidophone Voice Figures._ Margaret Watts Hughes.]

[Footnote 2: Mr Joseph Gould, Stratford House, Nottingham, supplies the
twin-elliptic pendulum by which these wonderful figures may be
produced.]

The following description is taken from a most interesting essay
entitled _Vibration Figures_, by F. Bligh Bond, F.R.I.B.A., who has
drawn a number of remarkable figures by the use of pendulums. The
pendulum is suspended on knife edges of hardened steel, and is free to
swing only at right angles to the knife-edge suspension. Four such
pendulums may be coupled in pairs, swinging at right angles to each
other, by threads connecting the shafts of each pair of pendulums with
the ends of a light but rigid lath, from the centre of which run other
threads; these threads carry the united movements of each pair of
pendulums to a light square of wood, suspended by a spring, and bearing
a pen. The pen is thus controlled by the combined movement of the four
pendulums, and this movement is registered on a drawing board by the
pen. There is no limit, theoretically, to the number of pendulums that
can be combined in this manner. The movements are rectilinear, but two
rectilinear vibrations of equal amplitude acting at right angles to each
other generate a circle if they alternate precisely, an ellipse if the
alternations are less regular or the amplitudes unequal. A cyclic
vibration may also be obtained from a pendulum free to swing in a rotary
path. In these ways a most wonderful series of drawings have been
obtained, and the similarity of these to some of the thought-forms is
remarkable; they suffice to demonstrate how readily vibrations may be
transformed into figures. Thus compare fig. 4 with fig. 12, the mother's
prayer; or fig. 5 with fig. 10; or fig. 6 with fig. 25, the serpent-like