ELECTRIC PHANOMENA OF THE ATMOSPHERE. 413 
of the resinous globe evaporates better under this electric in- 
duction. The vapours carry with them a resinous tension equal 
to that of the surface of the liquid, and they disperse in the atmo- 
sphere according to their specific weight and their repulsion as 
bodies charged with the same electricity. § 35. 
12th. The vapours thus dispersed react from above down- 
wards upon the electroscope; they place it in a resinous inclo- 
sure, and the instrument in rising or in lowering undergoes but 
feeble differences of reaction, or indeed sometimes does not 
undergo any appreciable change ; it is only by an ascension with 
a paper kite or a balloon that the extremity of the instrument 
can pass beyond this inclosure of homogeneous reaction. Assu- 
ming as a starting-point the induction obtained beneath a clear 
_ sky during a prolonged frost of 10° C. below zero, the diminu- 
tion of this induction will indicate the surplus of resinous va- 
pours contained in the atmosphere. § 13. 
13th. Fixed apparatus of small extent are useless in dry and 
clear weather ; they cannot render manifest electricity of induc- 
tion, since they remain at the place of their equilibrium; and 
they cannot radiate that retained on their surfaces, because 
the dry air is a good insulator. When they are of considerable 
length and are very high, the extent of the wire making up for 
the feebleness of the local radiation, the apparatus loses its elec- 
tricity of induction and becomes charged with permanent elec- 
tricity. § 43. 
14th. When the air is rather damp the radiation is favoured, 
and continuous currents may be obtained with shorter lengths 
of wire. § 43. 
15th. These electric phenomena arising from atmospheric in- 
ductions, must not be confounded with those which arise from 
the oxidation of the conducting wires immersed in a damp 
medium. This cause of error has often been the means of 
attributing to the atmosphere what belonged to a chemical 
action. § 43. 
16th. When by a depression of temperature the first vapours 
are condensed, they form opake clouds, and the electricity which 
they have carried away is distributed according to their group- 
ings and the ambient inductions. The induction of the earth 
renders these clouds more resinous in the upper than in the 
lower part; the electrometer will then diverge more beneath 
