1896 - 97 .] 
Chairman' s Opening Address. 
195 
take the matter np and apply it to an extent that, with numerous 
avocations and with calls to other branches of physiological research, 
I can never hope to overtake. 
The essence of the method consists in (1) driving at a very slow 
rate the mandrill carrying the wax cylinder of the phonograph on 
which a record has been taken. It is well to use well-marked 
records, and, if possible, those taken specially for purposes of investi- 
gation, at the time carefully noting the speed of the phonograph. 
The best speed I have found to be as nearly as possible that of one 
revolution in half a second. I now drive the mandrill a, as 
shown on the plate, by means of a small electric motor b, worked 
with one or two Obacli cells, V of the Q type, and the speed of 
revolution is one revolution in eight minutes, or nearly 1000 times 
slower than the speed at which the mandrill rotates when the 
phonograph is giving out tones. This slow speed gets rid of the 
inertia of the recording lever now to be described. 
On the ring bearing the apparatus for holding the glass dia- 
phragm, which has been removed, there is attached a light lever, 
cc 1 in plate, made of aluminium, rectangular in section, and so 
placed as to have the narrow borders above and below. This lever 
has its fulcrum in a well-made axle and pivot joint, c m in plate. 
It is continued backwards, as seen in plate, so that a small weight 
may, if necessary, be used as an equipoise. About 5 mm. from the 
pivot end of the lever, there is passing off from it, at right angles, 
an upright rod, c IV , shod on its lower end with the usual sapphire 
point of the reproducing phonograph. When this point rests on 
the wax cylinder, in the groove, and the cylinder moves slowly, as 
already described, it will be evident that this lever will move up 
and down, as the recording point slowly moves over the elevations 
and depressions on the cylinder, and that as the long arm of the 
lever, cc 11 in plate, is 205 mm. in length, the amplification at the 
point of the lever will be considerable. 
To secure still greater amplification, the point of this aluminium 
lever, which we will call the first lever , rests on a horizontal stiff 
rod, c7, 80 mm. in length, which is attached transversely to the short 
arm of another lever, to be termed the second lever. The fulcrum 
of this second lever is also a well-made axle and pivot arrange- 
ment; the short arm e (25 mm.) is horizontal, while the long arm / 
