18 
BRITISH ASSOCIATION.— 1835 . 
the reflected force, and attempted to prove that the whole attrac¬ 
tive force between these bodies varies with these forces conjointly, 
so that if one of them becomes fixed it varies with the other. He 
exhibited and described several new experiments in electricity re¬ 
lating to electrical induction and attraction, and expressed his opi¬ 
nion that the whole attractive force was dependent on the action 
excited in the neutral bodies reflected on the charged body. This 
principle, with but little modification, he further applied to any case 
of electrical attraction whatever. 
On the Application of the Proof Plane and Torsion Balance to in - 
quiries in Electricity. By W. Snow Harris. 
Mr. Harris conceives that an insulated plate of metal of small 
thickness may take up unequal quantities of electricity from a body 
and yet the distribution be uniform. The experiments in illustration 
of this were fully discussed. He alluded to several laws of elec¬ 
trical intensity attendant on the disposition of electricity on surfaces 
and plates varying in extension and in length, but of the same area, 
and endeavoured to show that contrary to the ordinary view of 
electrical distribution, electricity existed on both surfaces of a hol¬ 
low sphere, as well as on both surfaces of a plate of the same area. 
He considers every case of attraction in electricity to resolve itself 
into the case of charging a coated non-conducting body, and that 
the phaenomena always correspond to those observed in the latter. 
On the Aurora Borealis. By Sir John Ross. 
Having observed in his first arctic expedition that the aurora 
sometimes appeared between the two ships, and also between the 
ships and the icebergs, and found in his subsequent experience, 
both in Scotland and during the second arctic voyage, proofs satis¬ 
factory to his own mind that the aurora takes place within the 
cloudy regions of the earth’s atmosphere, Sir John Ross states the 
following hypothesis on the subject, viz. “ The aurora is entirely 
occasioned by the action of the sun’s rays upon the vast body of icy 
and snowy plains and mountains which surround the poles.” 
On an ceconomic Application of Electro-magnetic Forces to manufac - 
turing Purposes. By Robert Mallet. 
The separation of iron from brass and copper filings, &c., in 
workshops, for the purpose of the refusion of them into brass, is 
commonly effected by tedious manual labour. Several bar or 
horse-shoe magnets are fixed in a wooden handle, and are 
thrust, in various directions, through a dish or other vessel contain- 
