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Proceedings of the Royal Society 
the same observation was made by Dr Rontgen, and recorded by 
him in “Nature. It was interesting as being a proof of the 
actual vibration of the metallic substance at the distal tuning 
fork. 
2. Transmission of the Sounds of Organ Pipes. — If an organ pipe 
sounding loudly be brought into close proximity with a proximal 
telephone, its sound is heard distinctly at the distal telephone. If 
then a pipe of the same pitch be placed opposite the distal telephone, 
and it be sounded feebly, the sound is reinforced when the pipe 
at the proximal telephone is also sounding ; but I have never 
succeeded in causing one pipe actually to initiate sound in the 
other. Mr Aiken of Falkirk, however, has informed me by letter 
that he has observed this phenomenon. I found also that there 
was no intensifying effect when either of the disks was removed. 
3. Transmission of the Sounds of Vibrating Strings. — I succeeded 
in causing a string to vibrate by means of the telephone as follows : — 
Two catgut strings, each having a telephonic disk cemented to the 
centre of the string, were tuned as accurately as possible to a pitch 
of about C ; one disk was placed opposite a large and powerful 
telephone (the proximal), made by Mr William Bottomely, and the 
other (the distal), opposite a similar instrument ; on plucking the 
string at the proximal telephone, the string opposite the distal also 
sounded, though feebly. This experiment holds out the hope, that 
by suitable arrangements the sounds of strings might be transmitted 
for musical purposes. 
4. Optical Observations of the Movements of the Disk. — There can 
be no doubt (1) that sounds may be heard even when the disk is 
firmly pressed against the ear, so as to prevent its vibrations to a 
great degree ; and (2) that sounds may be heard even without any 
disk on the distal telephone. A disk, or moving metallic body 
capable of magnetic action, is always necessary at the proximal 
telephone. On the other hand, the existence of a disk, free to 
vibrate, at the distal telephone always intensifies the sound, and, 
in particular, it appears to be almost essential for distinct articula- 
tion of language. One would therefore infer that the disk must 
move as a whole. These movements I have studied in various ways, 
and they will still be under observation. 
ls£ method. — A strongly vibrating tuning fork was kept going 
