622 Proceedings of the Royal Society 
complete absence of magnetism, but they go far beyond the practical 
application of the word unmagnetic. The fork in question answered 
perfectly all these tests. I next tried to get sounds out of soft 
iron plates kept fixed above the coil, and found no difficulty 
in getting them to sound when laid on a table in a horizontal 
position and beaten with a small hard wooden mallet, or with 
something that would produce with them a sharp tap. When the 
plates were held approximately in the plane of the magnetic 
meridian there was more difficulty in getting the distant listener 
to hear, but even in it they did not cease to sound under blows 
sharp and hard enough. They also sounded when the coils were 
cemented to them, but the hearer had his powers taxed to catch 
the effect. Soft iron pins placed in the hollow axis of the coil 
also sounded under similar treatment. I could not succeed, how- 
ever, in getting a soft iron pin perfectly to answer the galvano- 
meter test, ordinary nails and similar iron pins always caused a 
slight deflection, which became more marked by pendulum accumu- 
lation. Even a soft iron pin, as pure as I could get, after being ex- 
posed for half an hour to a white heat, on being made to move at 
right angles to the dipping needle, at least so nearly as this position 
could be given to it by the hand, indicated through its coil faint 
traces of magnetism. I had some difficulty in getting taps out of it 
for the listening station, but I succeeded at last by using another 
similar pin held in the same line as a mallet. Iron thus softened 
seems to lose its telephonic power more by absence of elasticity 
than by being less magnetic, for the said pin seldom failed in any 
position before being annealed, and so far as tests went it was not a 
bit more magnetic. A somewhat curious result was got by cementing 
a small coil to a strip of ferrotype plate quite near to the edge, and 
making that edge strike on the teeth of a syren wheel, made to 
revolve on a turning table, when the screeching note thus produced 
was distinctly telephoned. When there was any slight indication 
of magnetism, such as was given by the spot of light shifting even 
a millimetre for one quick motion, the taps were rendered with 
great certainty. The soft iron pins just mentioned, when put on 
the pole of a magnet, and very gently tapped with a common 
pencil, made themselves distinctly heard. This can be done in 
the case of any telephone on removing the disc. 
