Scientific Intelligence. 111 
“SCIENTIFIC INTELLIGENCE. 
I, PHYSICS. 
1. Gemsbart Electroscope.—Prof. Kopett made an interesting com- 
munication to the mathematico-physical class of the Bavarian Academy 
of Sciences, in their session of Jan. 10th, 1863, on the electroscopie prop- 
erties of the so-called “ Gemsbart,” a name given by the Alpine hunters to 
the long hairs which grow along the back of the male Chamois in the au- 
tumn of the year, and are well known as the trophies with which the Ty- 
rolese hunter decorates his hat. These hairs from a four years’ buck reach 
d more, are very fine and generally terminate 
in a white point. If several are taken together by the root and stripped 
through the fingers, they repel each other to a great distance; if held by 
the points and rubbed towards the roots, a similar but weaker effect is 
electric. If both are attracted, the body is either non-electric, or a good 
conductor, in which latter case it must be insulated. To determine the 
examine it with the stronger + indicator, which has to be drawn through 
the fingers from time to time. By this method the poles of small crystals 
of boracite, thin needles of scolezite, calamine and Brazilian topaz were 
easily determined, small crystals generally giving a more constant and 
decisive reaction than larger ones. 
Highly electric crystals, as those of tourmaline, often show the poles 
plainly, even after they have become perfectly cool externally.. For their 
examination it is most convenient to attach the hair in the middle with 
wax to a Hauy’s needle, and at right angles to the same, and then in the 
aforesaid manner to excite the opposite electricities in the two ends, when 
the brass needle is immediately set in motion upon the approach of the 
electric tourmaline, and the poles can be distinctly shown by alternate 
repulsion and attraction. > 
€ two-fold electricity of such a hair is evidently connected with its 
re, for it is smooth from root to point, and feels rough in the 
opposite direction. This is corroborated by the fact, that, if a hair by 
frequent use has been made smooth in the latter direction, it changes 
___ its negative electric character into the positive. This occurs after about 
_ ne hundred experiments, when it can no longer be used as an — indicator. 
_ Prof. Bischof, who examined the hairs with the microscope, states that 
__ they have a highly developed epithelium, while the fibrous cortical sub- 
__ Stance is subordinate, and is almost entirely wanting towards the lower 
__ Part, where it is replaced by the epithelium. The cortical fibres, as usual, 
