abandoned. The white copper w' ic 
380° Prussian Blue. 
19. Electric Light.—Having a metallic wire covered 
with silk, form it into a close flat spiral, taking care that 
the revolutions touch each other. Their number may 
be arbitrary—more than twenty- -four have not been used. 
The properties of this spiral when it forms part of the 
voltaic circuit are well known, but pass through it a 
charge of common electricity, such as may be taken by 
two square feet of coated surface, moderately charged, 
and a vivid light, somewhat resembling that of an artificial 
fire-work, will occur, originating from the centre of the 
Spires, it may be seen very distinctly without darkening 
the chamber where the experiment is made. M. Leopold 
de Nobili, who describes this experiment, considers the 
ate ae as perfectly new. If the wire be folded 
ards and f orwards, so as to form a rectangular sur- 
hen electric. discharge only produces a faint 
ac | corner, and this he sHiRACae as the light 
by the escape of the « electric 
rainust dutty lent He has 
it eleutiostaeenones light, 
magnetic state of the spiral, thinks that it might be made 
continuous if a sufliciently powerful voltaic battery were 
used, and bas but little doubt that the aurora boxealer is. . 
such a hight, elicited by the magnetic state of the earth. — 
20. White Copper.—According to M. Keferstein, a meniiel 
composition resembling silver has been employed under the 
name of white copper, for a long time, at Suhl, in orna- 
menting fire-arms. M. Brandes, by analysis, found it to be 
an alloy of copper and nickel. M.M. Keferstein and Mul- 
ler have recently sought out the origin of this substance, 
and have ascertained that it is found in the scoria of some 
ancient copper works, formerly attached to mines now 
formerly been 
‘ejected as useless, is now nee 
peeve sageonee 
