266 Chronicles of Science. [ April, 
electro-positive metals, zinc, cadmium, iron, &c., induce in these in- 
sulators the negative condition—ebonite, gutta-percha, caoutchoue, 
waxed cloth, white wax, resin, shellac, sealg-wax, sulphur, amber, 
copal, silk, pyroxyline, collodion, and gun-cotton. There are a few 
exceptions in the behaviour of the metals. A good example of the 
general law laid down is furnished by ebonite. Gently rubbed 
with platinum it becomes positive, zinc or iron mducing the nega- 
tive condition. 
M. H. de Saussure has published a paper in the ‘ Bibliotheque 
Universelle,’ “ On the Humming Sound produced on Mountains by 
Electricity.” In June, 1865, M. de Saussure and a friend climbed 
the peak of Piz Surley. When the summit had been reached, sleet 
fell abundantly ; preparatory to taking their repast, they laid the 
alpenstocks against a little cairn of dry stones. Almost at the 
same moment, M. de Saussure felt acute pain in one shoulder, 
speedily in the other also, and in the back. The pain resembled 
the pricking of pins. Soon the alpenstocks resting agamst the 
rock commenced to sing loudly, the sound resembling that emitted 
by a kettle of water about to boil. Strong currents of electricity 
flowed from all the salient parts of the body, and the hair stood 
out. M. de Saussure remarks that in every instance where the 
phenomenon has been observed, the mountain peak has been enve- 
loped in a shower of frozen sleet. 
A new voltaic battery has been devised by Dr. Hugo Miller and 
Dr. Warren De la Rue. The negative element is chloride of silver 
fused around a silver wire, which serves as conductor; this wire is 
bent over and connected by means of a small caoutchoue collar to a 
rod of zine, which need not be amalgamated. The exciting liquid is 
salt water. In course of time the liquid becomes saturated with 
chloride of zinc; when metallic zine begins to deposit on the 
negative plate the battery must be renewed with fresh solution. 
The tension of a battery of ten cells (the couples being very small, 
about three inches in height) is sufficiently great to decompose 
water enough to yield a cubic inch of the mixed gases in about 
twenty minutes. Dr. De la Rue has constructed a battery of two 
hundred cells. 
M. Bourgoin continues his investigation regarding the electro- 
lysis of organic acids. The current acts on acetate of potassium as 
on a mineral substance. In a moderately alkaline solution the 
oxygen reacts on the elements of the anhydrous acid, giving rise to 
carbonic acid and hydride of ethylen. A certain quantity of acid 
is totally consumed under the influence of oxygen furnished either 
by the salt or by the alkaline water. The portions of liquid at the 
two poles suffer unequal losses; almost the whole is lost at the 
