10 Improvements in Physical Science [Jan. 
were put upon the top of a brass rod attached to the upper part of 
the prime conductor. The following is the order which the metals 
tried followed, beginning with the one which emitted the greatest 
quantity of light, and terminating with that metal which gave out 
the least light :— 
Antimony. Bismuth. Tron. 
Gold. Copper. Lead. 
Nickel. Tin. Soft steel. 
Silver. Zine. Hard steel. 
Brass. 
3. It is well known that the phenomena of galvanism have been 
accounted for by three different hypotheses, and that philosophers 
are not yet agreed which of these is the true one. According to the 
first opinion, which is Volta’s, the phenomena are purely electrical, 
and depend upon the different states of electricity in the two metals 
employed. ‘The chemical phenomena are merely accidental conse- 
quences of the electric discharge. According to another opinion, 
which is that of Berzelius, the phenomena are purely chemical, 
and the electricity is merely set at liberty in consequence of the 
chemical actions. A third hypothesis, that of Davy, unites the two 
preceding ones together, and considers the phenomena as partly 
electrical and partly chemical. 
Professor Pfaff, of Kiel, has published an elaborate examination of 
these three hypotheses. He endeavours to refute the hypothesis of 
Berzelius, and to establish that of Volta. I cannot pretend to give 
an abstract of this memoir here; because it could scarcely be ren- 
dered intelligible without a pretty full enumeration of the galvanic 
phenomena and experiments ; an enumeration which would take up 
much more room than J can possibly spare. But the memoir is 
well worthy of the attention of all those persons who are interested 
in electricity or galvanism. I know of no treatise in which a greater 
quantity of information on the subject is given in less space. (See 
Schweigger’s Journal, x. 179.) 
4. De Luc’s curious discovery of a dry galvanic pile which con- 
tinues active for years with little interruption, and likewise his ex- 
planation of the voltaic column founded on that discovery, and cn 
his previously published theory of electricity, are known, I pre- 
sume, to most of my readers, as they were published about five 
years ago in Nicholson’s Journal, and have attracted the general 
attention of electricians. Zamboni, Professor of Natural Philo- 
sophy in the Lyceum at Verona, has made an alteration in the con- 
struction of De Luc’s pile. He presented one of his electromotors, 
as they have been called, to the Royal Society, and they may be 
seen commonly enough in the mathematical instrument-makers in 
London. His pile consists of slips of silver paper laid on each other. 
On the unsilvered side of the paper is put a layer of black oxide of 
manganese and honey. These papers are piled above each other to 
the number of 2000. They are then covered externally with a 
