130 = Crosse’s E'xperiments with the Voltaic Battery. 
domestic purposes, and consisting mostly of silica. ‘Two wires = 
of platina connected either end of the brick with the poles of a : 
Voltaic battery of sixty three pairs of plates, each about two 
inches square. After many months’ action, silica in a — 
state formed in some quantity round the bottom of the brick, and 
as the solution evaporated, I replaced it by fresh additions, so 
that the outside of the glass basin, being constantly wet by re- 
peated overflowings, was, of course, constantly electrified. On 
this outside, as well as on the edge of the fluid within, I one day 
perceived the well known whitish excrescence, with its project 
ing filaments. In the course of time, they increased in number, 
and as they successively burst into life, the whole table on which 
bse apparatus stood, at last was covered with similar insects, 
hich hid themselves wherever they could find a shelter. Some 
be them were of different sizes, there being a considerable differ- 
~ence in this respect between the larger and the smaller ; and they 
were plainly perceptible to the naked eye, as they nimbly crawled 
from one spot to another. I closely examined the table with a 
lens, but could perceive no such excrescence as that which marks 
their incipient state, on any part of it. While these effects were 
taking place in my electrical room, similar formations were 
making their appearance in another room, distant from the for- 
mer. I had here placed on a table three Voltaic batteries, uncon- | 
nected with each other. The first consisted of twenty pairs of | 
two-inch plates, between the poles of which I placed a glass cyl- | 
- inder, filled with a concentrated solution of silicate of potassa, | 
in which was suspended a piece of clay slate by two platina 
wires connected with either pole of the battery. A piece of pa- 
per was placed on the top of the cylinder, to keep out the dust. | 
After many months’ action, gelatinous silica in various forms was | 
electrically attracted to the slate, which it coated in rather a sin- 
gular manner, unnecessary here to describe. In the eourse of 
time, I observed similar.insects, in their incipient state, forming 
around the edge of the fluid within the jar, which, when perfect, - 
crawled about the inner surface of the paper with great activity. 
The second battery consisted of twenty pairs of cylinders, each 
equal to a four inch plate. Between the poles of this, I interposed 
a series of seven glass cylinders, filled with the following concen- 
of copper: 2. Sub-carbonate of po- 
: 4. Green sulphate of iron: 5. 
