252 
SECOND REPORT - 18S2. 
It is worthy of remark that notwithstanding the enormous 
annual fall of rain at the equator, particular instances of a great 
depth of rain in a short time have occurred (though rarely) in 
Europe, which probably have seldom been equalled by authen¬ 
tic observations in any part of the globe. At Geneva, on the 
25th October 1822, there fell thirty inches of rain in one day*. 
An example equally extraordinary has recently been quoted by 
M. Arago, and which is perfectly authentic. At Joyeuse in 
the department of the Ardeche, on the 9th October 1827, there 
fell 29 inches 3 lines French measure (above 31 inches English) 
of rain in 22 hours f. 
The subject of Atmospherical Electricity excited in the 
middle of the last century an unexampled degree of interest in 
consequence of the fine discoveries of Franklin ; and the appli¬ 
cation of thunder-rods produced a more vehement spirit of dis¬ 
cussion among all classes than is usually to be met with on any 
purely scientific question. This excitement was naturally suc¬ 
ceeded by a degree of apathy ; and it must be admitted, that 
whilst every department of the noble science of electricity has 
been illustrated with triumphant success by Coulomb, Davy, 
Oersted, Faraday, and many others, its application to Meteo¬ 
rology has been strangely neglected, and in fact, on this im¬ 
portant subject almost everything has yet to be done. On the 
general subject of atmospherical electricity, the principal con¬ 
tributions which we have to notice are those of M. Pouillet, to 
whom we owe some very interesting experiments in electrical 
science. 
One great question on this subject is the source of the vast 
amount of electricity which seems, as it w^ere, perpetually 
created in the atmosphere, and which, notwithstanding the 
constant recombinations which are going forward, remains 
sensible, according to the experiments of Lemonier, Saussure, 
and others, during the most steady and cloudless weather. 
M. Pouillet has very happily shown two causes in constant oper¬ 
ation which create this abundant supply J. The first of these 
is vegetation. M. Pouillet has proved by direct experiment 
that the combination of oxygen with the materials of living 
plants, is a constant source of electricity ; and he has shown 
that a surface of 100 square metres in full vegetation disengages 
* Pouillet, Elemens de Physique, ii. 758. 
f Annales de Chimie, xxxvi. There are some interesting collections relative 
to the fall of rain at different places, in Schouw’s Specimen Geographies Physi- 
ccs Comparatives , 4to, 1828. 
X Annales de Chbnie et de Physique, 1827. See also his Elemens de Phy¬ 
sique, liv. ix. chap. 5. 
