Electricity of Human Bodies.

Editor Scientific American.

In the year 1838, happening to be in Baltimore, I met with an intimate friend of mine, who informed me of some curious experiments he had been making in electricity. Reflecting on the curious phenomenon observable on the friction of the hair of a cat's back, well known to everybody, he was induced to try the operation on the human head, when to his gratification and astonishment he discovered that powerful discharges of electricity could in this way be readily obtained. The manner of experimenting is as follows: Let a person be seated in a chair the four legs of which are placed in as many glass tumblers for the purpose of insulation. Then if a horn or wood comb is rapidly drawn through the hair by another person (who must carefully avoid touching the subject of the operation as the electricity would be thus carried off,— sparks may be readily taken from any part of his body by the application of one's finger. I tried the experiment myself at that time, and by means of a Leyden jar obtained twenty five sparks, with which I shocked seven or eight persons formed into a circle. If a metal comb be used, flashes of light can be distinctly seen in a dark room, coursing from the hair along the comb to the hand of the operator. What is worthy of notice, as tending to prove that all living organizations throw off electricity continually at every effort of muscular exertion, is the fact that if the insulated individual combs his own hair, no sparks can be obtained. The gentleman who made these observations, also discovered the "electricity of steam," and communicated the fact to me at that time, which was several years before its announcement in England.

Your, &c. T. H.

P. S. Persons unacquainted with the phenomena of electricity who may try the above experiments, may need to be informed that a cold room is the best in which to make them.

JERSEY CITY NOV. 25, 1846,

MrEditor, .

In accidentally looking through white or milky colored glass I perceived that the light from the lamp was of a blood red color. The experiment excited my curiosity, and a variety of suggestions presented themselves to the mind. I was led, among other things, to infer that the red appearance of the sun and moon in smoky weather might be produced by a principle analogous to that here instanced, or that it is likely one and the same effect.

Would you be good enough to explain in your excellent paper the nature of this phenomenon, and oblige your, M.

There are different kinds of white glass and we are not prepared to say what ingredient produces the effect above described, but it is evident that the glass may contain a transparent red color concealed by an opaque white. For example, if white lead be mixed with common red ink, the red color will disappear, but if a thin coat of this paint be spread over glass it will change the sun's rays to a red color, though it appears white of itself.—ED.