1864. | Physics. 505 
Whilst the electrical relations of metals, &c., in aqueous solutions 
of acids, alkalies, and salts, have been repeatedly, and we may almost 
say exhaustively examined, few, if any, experiments have been made on 
the similar relations in fused substances. This gap has now been filled 
up by Mr. Gore,* who has examined the electrical relations of carbon, 
magnesium, aluminium, silicium, zinc, tin, lead, iron, nickel, copper, 
silver, gold, and platinum, in sixty-seven salts or mixtures of salts 
kept in a state of fusion, in small porcelain crucibles, either by an or- 
dinary Bunsen burner, or when difficultly fusible, by one of his small 
gas furnaces already described in this Journal. The results are care- 
fully tabulated, and amongst others it is found that the most negative 
substances in fused salts are generally platinum, gold, carbon, and 
silver ; the most positive substances are generally magnesium, alu- 
minium, and zinc. Silicium is generally electro-positive to carbon, 
and is strongly positive, and quickly corroded in fused alkalies, alka- 
line carbonates or fluorides. Carbon is not generally very positive to 
iron. This investigation throws some light upon the desirable object 
of obtaining a cheap source of electricity by the combustion of coke or 
gas carbon. The discovery of some suitable fused salt or mixture, in 
which carbon is highly electro-positive at a high temperature to iron, 
nickel, or other infusible and suitable conductor would probably prove 
a cheap and powerful source of electricity : cheap, because of the low 
equivalent number of carbon, and the low price of coke and gas carbon ; 
and powerful, because of the intense affinity of carbon for oxygen at 
high temperatures,—an affinity sufficient, indeed, to set the alkali 
metals free from their oxides. The nearest approach in these experi- 
ments to this object was with carbon and nickel in a fused mixture of 
soda, lime, and silica. 
Many experimentalists have examined the stratified light of the 
electric discharge, and have assigned various causes for this curious 
phenomenon ; they seem, however, all to have ended in the establish- 
ment of one fact only, that the alternate light and dark bands require 
for their production an imperfect conductor. M. L’Abbé Laborde + 
has lately succeeded in producing an analogous stratified appearance, 
and permanently fixing it on a plate of glass. For this purpose he 
prepares a glass plate with iodized collodion, and then lets it undergo 
all the operations customary in preparing a photographic image. It is 
exposed for a brief time to light, and then the silver is reduced by a 
developing agent. A surface is thus obtained which possesses an in- 
termediate conductibility. The two ends of the induction wire being 
placed a little distance apart on the surface, the spark will produce 
stratification in passing from one to the other. A suitable surface 
cannot invariably be obtained ; when the plate presents the appearance 
known as solarization, and has a reddish transparent tint, the surface 
is not sufficiently conducting, and the spark passes over without at- 
tacking it. If on the contrary the silver is completely reduced, and 
presents a metallic and mirror like layer, it conducts too well, and the 
* «Chemical News,’ June 4, 1864. 
+ ‘Comptes Rendus,’ lviii. 661. 
