1852.] OF THE ROYAL INSTITUTION. 121 
_ In the cases of heating or ignition of a conjunctive wire or con- 
ducting body through which what is called Electricity is transmitted, 
we have many evidences that the matter itself is affected, and in some 
cases temporarily, in others, permanently changed; thusif a wire of 
lead is ignited to fusion by the voltaic battery, the fused lead being 
kept in a channel to prevent its dispersion, it gradually shortens, 
and the molecules seem impressed with a force acting transversely 
to the line of direction of the electricity ; at length the lead gathers 
up in nodules which press on each other as do, to use a familiar 
illustration, a string of figs. 
With Magnetism we have many instances of the molecular change 
which a ferreous or magnetic substance undergoes when magnetized. 
If the particles are free to move, as for instance iron filings, they 
arrange themselves symmetrically. An objection may be made 
arising from the peculiar form of the iron filings, but Mr. Grove in 
the year 1845, shewed that the supernatant liquid in which magnetic 
oxide had been formed, and which contains magnetic particles not 
mechanically but chemically divided, exhibits when magnetized a 
change in the arrangement of the molecules, as may be seen by its 
effect on transmitted light ;—-a molecular change is also evidenced 
by the note or sound produced by magnetism, and by other effects. 
Assuming that the molecules of iron change their position inter se 
upon magnetization, then by repeated magnetization in opposite 
directions, something analogous to friction might be produced ; and 
just as a piece of caoutchouc when elongated produces heat, (as it was 
on this occasion experimentally shewn to do) soa bar of soft iron 
might be expected when subjected to rapid changes in its magnetic 
state, to exhibit thermic effects. 
With the aid of the large magnet of the Institution and of a 
commutator for changing the direction of the Electricity a bar of 
soft iron was alternately magnetized in opposite directions ; and in a 
few minutes a thermometer placed in an aperture in the iron shewed 
a rise of temperature of 1, 5° Fahrenheit ; the bar being separated 
from the magnet by flannel, and the magnet being at a notably lower 
temperature than the bar, this heat could in nowise be attributed to 
conduction. 
The effect of Electricity in the disruptive discharge as in the Voltaic 
are and the electric spark, would seem at first sight to offer greater 
difficulties of explanation on the dynamic theory. The brilliant 
phenomenal effects of the electric discharge, and the apparent absence 
of change in the matter affected by it, would at first lead the observer 
to believe that Electricity was a specific entity. 
With ordinary flame or the apparent effects of combustion however, 
the idea has to a great extent been abandoned that such visual 
effects are due to specific matter, and it is regarded by many as an 
intense motion of the particles of the burning body. So with 
Electricity, if in regard to the disruptive discharge it can be shewn 
that the matter of the terminals or of the intervening medium is 
changed, the necessity for the assumption of a fluid or ether ceases, 
and, to say the least, a possibility of viewing Electricity as a motion 
or affection of ordinary matter is opened. 
