Address of the President of the Royal Society. 113 
2. The identity of voltaic with frictional electricity was denied by 
many, because it gave no spark through an interval of air, Davy h 
indeed, asserted the contrary in his ‘Elements of Chemical Philosophy ; 
but his statement seems to have been doubted or unheeded. Mr. Gassiot, 
in the Transactions for 1844, has put the fact beyond dispute ; he showed 
ells, the same or even greater effect could be produced by a much 
smaller series. The battery of 500 Grove’s cells, which was constructed 
for these experiments, is probably in some respects, the most powerful 
that was ever made. 
3. The currents produced by electric or magnetic induction are of 
the highest interest, and the employment of them as a so ree of electri 
In this new field Mr. Gassiot has been one of the most successful explorers. 
So early as 1839 he showed that the induction-current gives a real spark, 
and he found that in the flame of a spirit-lamp it could strike at a dis- 
tance of #ths of an inch. 
understood, but Mr. Gassio made some very important additions to 
our knowledge of it in the Bakerian Lecture for 1858, and his subsequent 
communications to the Society. ng these may be named his explan- 
sealed; then, by heating the potassa, th 
’ i. Vessels so e: 
or even totally, absorbed 
t d 
alkali is vaporized by heating them, and the gradual progress of the ex- 
haustion gives a wide range of observation, wt Us ‘ 
5. gs of an induction machine is necessarily intermittent, 
it supposed that the strata are in some way caused by the 
rmittence, and are possibly connected with the mode of action of the 
* Aw Jour. Sct.—Ssconp Series, Vou. XXXVII, No. 109.—Jan., 1864. 
15 
