Proceedings of Scientific Bia 385 
through the whole capacity of the air, is of very feeble intensity, although — 
of great quantity; but the condensation of the vapor into a cloud affords 
a continuous conductor, and consequently the electricity of all the parti- 
cles of the interior, according to the well known principles of distribu. 
tion, rushes to the surface of the cloud, and hence the great intensity of 
“the lightning. According to this hypothesis, the insulated conductor, 
placed in the steam, would act not only asa collector, but also as a con- 
denser of the free, but feeble electricity of the vapor. 
Prof. Henry farther stated, in connection with this subject, that he had 
been informed by several persons, that they had obtained sparks of elec- 
tricity from a coal stove during the combustion of anthracite. A case 
had been stated to him several years ago, which he mentioned to his 
friend, Professor Bache, who informed him that a similar one had fallen 
under his own notice, in which, however, Prof. Bache had succeeded in 
tracing the electricity to the silk shirt of the person who drew the spark. 
Another case had lately been reported-to him by an intelligent gentleman, 
of a stove burning bituminous coal, on board of a steamboat on the Ohio, 
which afforded amusement to all the passengers during the voyage, by 
giving sparks of electricity whenever it was touched. 
Th connection with the facts that had been stated of the production of 
electricity from steam, Prof. Henry observed that he was now inclined to 
believe that electricity may also be evolved during the combustion of coal 
ina stove. But what, he asked, is the source of electricity in this case? 
Is it combustion, the evaporation of the moisture, or the friction of the 
hot air on the interior of the pipe? 
. Goddard stated, that in the case of a stove, pretty well insulated, 
his family had amused themselves with drawing sparks half an inch or 
three quarters of an inch long; and that similar sparks were obtained 
from the frame of a looking-glass over an open grate, in the house of Dr. 
Norris, of this city. . 
Professor Bache remarked, that in the case referred to by Prof. Henry, 
in which sparks of electricity were obtained from a stove, he had satisfied 
himself that these: were owing to the experimenter wearing a silken 
Shirt:—an experimenter, not similarly clad, being unsuccessful. 
‘Dr. Hare ascribed the incredulity and the opinions which he had ex- 
Pressed, when this subject was brought before the society by Mr. Pp eale, 
at the last meeting, to a misapprehension, on his part, as to the circum- 
stances. He considered that the fact of electricity being developed in 
the case adduced, was established. He alluded to the almost incredible 
Case of a lady, who, agreeably to evidence mentioned in Silliman’s Jour- 
nal, Vol. xxi, gave off sparks of electricity. He stated also the result 
of an experiment to discover whether electricity was geen off during the 
rapid evaporation of a saline solution. ‘There was no evidence of excite- 
ment. The vessel was of glass. 
