116 Chronicles of Science. [Jan., 
remarkable intensity and brilliancy; if at the same time, the other 
end of the secondary wire is put in communication with one of 
the poles of the pile, a great increase takes place in the brilliancy 
of the spark. Then, on touching with the hand the iron core, and 
placing the free end of the wire in contact with the skin, a redness 
takes place, and a smart stinging sensation is felt. This last expe- 
riment was made upon a coil, the core of which, completely isolated 
in a tube of varnished glass, was eight millimetres in diameter. 
M. Rondel made the same experiment with another bobbin, the 
soft iron of which was twelve centimetres long, five centimetres 
wide, and eight millimetres thick. The sparks were produced with 
detonations. A single Bunsen element of small size was sufficient 
to produce these phenomena. 
A note on the Polarization of Electrodes—a subject of consi- 
derable interest to telegraphists and electricians—has been presented 
by M. Gaugain to the Academy of Sciences. Several savants have 
sought to determine the part which each of the electrodes takes in 
the polarization, and have arrived at different results: M. Poggen- 
dorff found that the two electrodes contributed equally to the 
production of the electromotive force developed; MM. Lenz and 
Sarvelgen found, on the contrary, that the part of the cathode 
is greater than that of the anode. M. Gaugain has tried, in his 
turn, to resolve the question by making use, as he did on former 
occasions, of the method of opposition. The following are the 
results thus obtained by a series of experiments carried on with a 
mixture of nine parts by volume, of distilled water, and one part of 
sulphuric acid :— 
Polarization of the anode .. Bo S13 ate es oa AOS: 
4 of the cathode oo ae ae 56 so LOU 
Total polarization ie ac ve 350 
It appears to be of little consequence, if more or less sulphuric 
acid be added to the electrolyzed water, provided that this propor- 
tion does not fall below a certain limit; but when it becomes 
extremely small, the polarization of the cathode increases, without 
the polarization of the anode being sensibly modified. The following 
are the results obtained by electrolyzing pure water :— 
Polarization of the anode cts oe ie bs Js “193 
9 of the cathode ei te “% ae vs ©6243 
Total polarization ac oF os 436 
M. Matteucci recently * called the attention of the Academy 
to an experiment which he made in 1838, and upon which he 
* «Comptes Rendus’, Jan. 14, 1867. 
