208 Sir Graves C. Haughton’s Experiments in Electricity. 
believe, by Davy, and afterwards more explicitly mentioned 
by Berzelius, that the heat of combustion is an electrical phee- 
nomenon, is now rendered sufficiently evident. We have also 
shown that the heat arises from resistance to the conduction 
of electricity between the atoms of combustibles and oxygen 
at the moment of their union. Of the nature of this resist- 
ance we are still ignorant. 
Some time ago I commenced an investigation on the heat 
arising from the union of sulphuric acid with potash, soda, 
and ammonia. ‘This inquiry is more difficult than I expected, 
and my experiments are not yet sufficiently complete to lay 
before the British Association. In a future paper I hope to 
extend my inquiry, and also to show the relation of latent heat 
to electrical intensity. 
XXXIV. Experiments in Electricity. 
By Sir Graves C. Havenrton, K.H., F.R.S. 
To the Editor of the Philosophical Magazine and Journal. 
Sir, 
As’ every phenomenon connected with electricity must be 
interesting to the scientific world, whether it brings to 
light a new principle or merely confirms one that has been 
already established, I have thought that the following experi- 
ments might prove acceptable to your readers. 
If a needle of any of the malleable metals, or of other sub- 
stances, such as wood, ivory, quill and straw, or even of glass 
or sealing-wax, be placed in a galvanometer of the simplest 
form, and one end of the wire be fixed in metallic contact to 
the hook of the prime conductor of an electrifying machine, 
less than a quarter of a revolution of the handle will, if the 
machine be in good working order, cause the needle to stand 
at an angle of 90°. If the proper needle of the galvanometer 
be employed instead of one of the foregoing, it will place itself 
at an angle of from 75° to 80°, and will preserve that position 
as long as the machine is kept in operation. The needles 
with which these experiments were tried varied in length from 
three inches to five-eighths of an inch. The galvanometer 
stood at first simply on a mahogany table, but the results were 
not certain with every kind of needle, owing apparently to 
their faulty construction; when, however, it was placed on a 
good insulator the experiments never failed. It is worthy of 
remark, that whenever the state of the atmosphere was unfa- 
vourable to the working of the machine, which has been uni- 
formly the case during the present month, in consequence of 
