PHILOSOPHICAL TRANSACTIONS. 
I. On the Vibrations and Tones produced hy the Contact of Bodies having different 
Temperatures. By John Tyndall, Ph.D., F.R.S., Member of the Royal Society 
of Haarlem, and Professor of Natural Philosophy in the Royal Institution. 
Received January 15, — Read January 26, 1854. 
In the year 1805, M. Schwartz, inspector of one of the smelting- works of Saxony, 
having a quantity of silver in a ladle which had just solidified after melting, and 
wishing to hasten its cooling placed it upon a cold anvil, when to his astonishment 
sounds, which he compared to those of an organ, proceeded from the mass. The 
rumour of this discovery excited the curiosity of Professor Gilbert, the editor of 
Gilbert’s Annalen, and in the autumn of the same year he paid a visit to the smelt- 
ing-works in question. He there learned that the piece of silver from which the 
sounds proceeded was cup-shaped, had a diameter of 3 or 4 inches and a depth of 
half an inch. Gilbert himself, under the direction of M. Schwartz, repeated the 
experiment. He heard a distinct tone, although nothing that he could compare to 
the tone of an organ. He also found that the sound was accompanied by the 
quivering of the mass of metal, and that when the vibrations of the mass ceased, the 
sound ceased likewise. The Professor limited himself to the description of the phe- 
nomenon and made no attempt to explain it. 
In the year 1829 Mr. Arthur Trevelyan was engaged in spreading pitch with a 
hot plastering iron, and observing in one instance that the iron was too hot, he laid 
it slantingly against a block of lead which happened to be at hand. Shortly after- 
wards he heard a shrill note, resembling that produced on the chanter of the smaller 
Northumberland pipes, an instrument played by his father’s gamekeeper. Not know- 
ing the cause of the sound he thought that this person might be practising out of 
doors, but on going out the tone ceased to be heard, while on his return he heard it 
as shrill as before. His attention was at length attracted to the hot iron, which he 
found to be in a state of vibration, and thus discovered the origin of this strange 
music. In 1830 he came to Edinburgh and mentioned the fact to Dr. Reid ; the latter, 
MDCCCLIV. 
B 
