SCIENCE. 
1 1 
ELECTRICITY. 
An interesting experiment, which seems to have a bear- 
ing on the action of Edison’s friction telephone, has been 
recently described by Herr Koch. When a plate of plati- 
num or palladium is polarized by means of an electric cur- 
rent, the friction of these metals against a plate of moist- 
ened glass increases immediately. To measure the friction, 
Herr Koch uses the metal in the form of a hemispherical 
button, resting on the bottom of a glass cup, filled with 
pure or acidulated water. The button serves as pivot to a 
magnetic needle, which oscillates under the action of the 
earth ; the decrease of the oscillations measures the friction 
of the pivot. Polarization is produced by the current of 
the Daniell element, one pole of which communicates with 
the metallic button, while the other terminates with a plati- 
num wire entering the water of the cup. The polarization 
by hydrogen produces no effect, but polarization with the 
pole oxygenated is found verv efficacious. The friction 
was increased, through this polarization, in the ratio of 2 
to 3, and sometimes in that of 2 to 4. This increase of 
friction appears immediately the circuit is closed, and dis- 
appears immediately when the current is reversed ; but it 
disappears slowly, like the polarization itself, when the 
circuit is merely opened. It increases with the electromo- 
tive force of the polarization by oxygen. Palladium behaves 
like platinum. Gold (18 carat) gave no effect. 
M. Desprez has lately attacked the problem of transmit- 
ting, by means of an electric current, the motion of a motor 
A to a receiver at some distance B, as a rigid axis between 
the two would do, so that the angular velocity of B should 
be always equal in amount and sign to that of A. (The 
particular case was that of getting within a railway carriage 
a rotation identical with that of the motor wheels of the 
locomotive.) On the shaft of the transmitter A are fixed 
two commutators, each of which reverses the current that 
traverses it twice each turn ; but the positions of the shaft 
corresponding to these inversions do not coincide; they 
follow each other at intervals of a quarter of a turn. The 
receiver consists of a permanent magnet or electro-magnet, 
between the branches of which are two straight electro- 
magnets, capable of rotating round an axis which coincides 
with that of the magnet. The currents sent through these 
electro-magnets from the shaft A produce the desired effect. 
This apparatus (it is noted) effects the transmission of work 
of a motor from one point to another with conservation of 
the angular velocity (which has not been realized in any 
electric motor hitherto used), the latter varying from o to 
2,400 turns per minute. The alternating currents required 
may be generated by a magneto-electric machine. Again, 
any motion may be considered as the resultant of two 
movements of rotation ; hence this apparatus, with a simple 
mechanism added, would serve for transmission of a motion 
of drawing, or writing. 
The steadiness of the incandescent light over that of 
the arc has long been understood, but hitherto the cost of 
the one has been so great that practically it was out of the 
question for general use. This will account for the little 
progress made by the Werdermanu light. The cost is due 
principally to the consumption of carbon. Again, it is well 
known that the consumption of carbon, in an atmosphere 
containing no oxygen, or in a vacuum, is reduced to a 
minimum. Many inventors have tried to make lamps to 
retain a perfect vacuum, but have failed. It is easy, how- 
ever, to make a water-tight joint, and by surrounding this 
with water Mr. Brougham has solved one of the problems 
of the incandescent lamp. The oxygen originally in the 
lamp globe is quickly exhausted, and then the atmosphere 
consists of gases which do not combine with carbon, and 
the result is very slow combustion or disintegration. The 
water-tight joints having been obtained in the manner 
above indicated, the globe is partially filled with water, so 
that when placed over the lamp globe, the water is well 
over the cap. This water globe is fastened by means of 
clamps and screws. The inventor states that while the 
carbon burns away at the rate of six inches per hour in the 
open air, it burns only one-eighth of an inch perhour when 
in the water-covered globe. This shows an enormous sav- 
ing in the cost of carbon, and if it can be shown that the 
saving thus obtained is greater than the cost of the extra 
power absorbed by the incandescent lamp over that of the 
arc, a decided step will have been made towards furnish- 
ing a light that can without difficulty be applied to ordinary 
sized rooms. We have seen this lamp, and can testify as 
to its steady light. 
So long as the liquid in the vessel is above the cap of 
the lamp, no atmospheric air can enter the lamp globe, and 
at the same time the heat from the lamp is carried off or 
dispersed and the light diffused. Provision may be made 
for the removal and replenishing of the liquid in or for 
causing it to circulate, but we are of the opinion that 
the ground-glass globe will prove more satisfactory as it is 
than any addition to the apparatus can make it. We made 
inquiries as to the liability of the copper wedge to melt, 
but its size and its connection with so large and such good 
conductors removes all tendency in this direction. — Elec- 
trician. 
A simple method of perforating glass with the electric 
spark is described byM. Fages in a recent number of La 
Nature. The apparatus required consists (1) of a rectangu- 
lar plate of ebonite, its size, for a coil giving 12 ctm. sparks, 
about 18 ctm. by 12 ; (2) of a brass wire passing under the 
plate and having its pointed end bent up and penetrating 
through the plate— not farther. This wire is connected 
with one of the poles of the coil. A few drops of olive oil 
are placed on the ebonite plate about the point, and the 
piece of glass to be perforated is superposed, care being 
taken not to imprison any bubbles of air. The olive oil 
perfectly accomplishes the object of insulating the wire. 
One has then only to bring down a wire from the outer pole 
of the coil, on the piece of glass, above the point of the 
lower wire, and pass the spark. By displacing the glass 
laterally for successive sparks, it is easy to make a close 
series of holes in a few seconds. 
A new form of electric lamp has been invented by Mr. 
Charles Stewart, M. A. It consists of a number of square 
carbon rods placed radially upon a disc of wood, or metal, 
in such a manner that the inner ends of the carbon rods 
form a complete circle. There is a circular opening in the 
wooden disc through which the electric light is seen from 
underneath. The carbons which are all forced toward the 
centre by a uniform pressure, move forward as they are 
consumed, and together form the positive electrode of the 
lamp. The negative electrode consists of a covered hemis- 
pherical cup of copper which before the current enters the 
lamp, rests upon the ring formed by the carbons. On the 
current entering the lamp an electro-magnet raises the 
metal electrode, and the electric arc is then formed between 
the circle of carbon and the metal electrode. There is a 
flow of water through the latter to keep it cool. The inven 
tor claims for his lamp the following advantages. (1). It is 
automatic in its action. (2). Burns for a considerable per- 
iod. (3). Throws no shadows. (4). Simple and inexpen- 
sive in structure. (5). The intensity of the light may be in- 
creased if desired. 
The Telegraph and Earthquakes. — A recent letter 
from Mr. W. A. Goodyear, now director of the governmental 
mining and geological survey of San Salvador, states that 
more than 600 shocks of earthquakes were felt there during 
the last ten days of 1879. They were heaviest about Lake 
Ilopango, where a shock occurred on the 23rd of December, 
which broke the telegraph wire asunder and “ made the 
ground on which we stood a perfect network of cracks, 
opened new springs of water, increased the rivulets in the 
vicinity to ten times their usual volume, muddied the waters 
of the lake in many places, and rolled hundreds of thousands 
of tons of rocks down the steep hills in the form of land- 
slides.” As a sequal to these earthquakes, came the irruption 
of a volcano in the middle of Lake Ilopango on the night of 
January 20th to 21st. The volcanic island resulting now 
measures over five acres in extent, and shoots up a column 
of steam into the air over 1000 feet in height. This is the 
first instance we have heard of earthquakes interrupting land 
telegraph lines, though there are cases on record of their in- 
terrupting cables. 
