1878.1 
The British Association. 
521 
so that up to the present time no observations have been 
received. 
Mr. W. Ladd read a paper “ On Edmunds’s Phonoscope.” 
This instrument is for producing figures of light from 
vibrations of sound. It consists essentially of three parts — 
an induction coil, an interrupter, and a rotary vacuum tube. 
The aCtion of the instrument is as follows : — Sounds from 
the voice or other sources produce vibrations on the diaphragm 
of the interrupter, which, being in the primary circuit of the 
induction coil, induce at each interruption a current in the 
secondary coil, similar to the aCtion of a contaCt-breaker or 
rheotome ; therefore each vibration is made visible as a flash 
in the vacuum tube. The tube revolving all the time at a 
constant speed, the flashes produce a symmetrical figure 
like the spokes of a wheel, as in the Gassiot star. The 
number of spokes or radii is according to the number of 
vibrations in the interrupter during a revolution of the 
tube, and the number of vibrations being varied to any 
extent according to the sounds produced, the figures in the 
revolving tube will be varied accordingly. The same sounds 
always produce the same figures, provided the revolutions 
be constant. In case of rhythmical interruption being pro- 
duced in a given sound, as in a trill, most beautiful effects 
are noticeable, owing to the omission of certain radii in 
regular positions in the figure. The uses of this instrument 
are the rendering visible of sounds, and showing the vibra- 
tions required in their production, and it forms a mode of 
confirming by sight an appeal to the ear. 
The next paper was by the same author, “ On Byrne’s 
Compound Plate Battery,” described in the last number of 
the “ Quarterly Journal of Science.” 
Prof. G. Forbes described “ A Clock with a Detached 
Train.” In the course of some experiments still progressing 
he used a clock to give eleCtric signals every second. It has 
a train of only one wheel working in a pinion. It is driven 
by a weight which falls through 5 feet in an hour. This 
clock only goes one hour, but serves the purpose for which 
it was made. He wished lately, however, to make it go for 
a longer time, so he drove it by a weight hung by a pulley 
on an endless chain in the usual way, and he attached a 
common five shilling Swiss alarm clock to the chain to wind 
it up continuously. This answers so well that he would 
suggest a similar construction as not only the cheapest, but 
also the best form of a clock with escapement. It consists 
of a pendulum and escapement with no train whatever, with 
