

AN ELECTRIC BATTERY FOR THE LABORATORY, ETC. 149 

plates upon the sides of the cells, whence it may easily be detached 
with a wooden knife. This copper, free from metalloids, will fetch 
a high price for the fabrication of conducting wires and of certain 
alloys. Its price will of course have to be deducted from the 
general outlay. 
Nothing limits us in the choice of forms and dimensions for the 
cells and the zincs. ‘These latter, moreover, with their partitions 
can be folded or bent, which gives an increase of exposed surface 
in a given space, always as if it were a question of a battery with a 
single liquid. 
The couples of our smallest model have the following dimen- 
slons—Zinc: length o".333; breadth o™.160. Cell: length o™ 
-440 ; breadth o™.050; height 0.220. 
For this form the constants are—E==1"" .07 ; R—o™™ .14, 
The consumption per twenty-four hours, when results close upon 
the maximum are obtained, would be practically 1 kg. sulphate of 
copper 0.4 kg., zinc about 0.1 kg., with a production of close upon 
0.90 kg. of metallic copper. - 
We have in use a battery of sixty-eight small couples. It occu- 
pies a place under the windows of the hall in a small yard of a 
width of two metres, which separates the house from the street. 
This battery is employed alternately in supplying light for the 
laboratory and the house, by means of Faure accumulators. 
For the laboratory it is a sure and convenient electromotor, the 
use of which will obviate many of the difficulties previously ex- 
perienced. 
When applied to illumination the battery, in connection with 
thirty-six Faure accumulators, will supply five incandescent lamps 
in free air for five hours. We reckon that it would supply from 
eighteen to twenty Edison lamps for the same time. In either 
case the expense for an equal amount of light would be much 
higher than that of gas, but a little less than that of stearine wax. 
Applied to the production of motive force, the same battery 
would cost about 2 fr. 70 cents. for 60,000 kilogrammetres. 
The expense, though much greater than that of machines, 1s 
less than with the batteries hitherto in use. We are endeavouring 
to reduce the net cost still further. 
For all this, we believe that in the condition in which our battery 
is now presented, it may be at once admitted into laboratories and 
adopted by amateurs for domestic use.—Za Nature. 
Nore.—Dr. Henri Van Heurck writes us that he has had a 
battery of 40 of these elements working for the past two months 
to his entire satisfaction. : 
Referring to our note on p. 129 of the present volume, the Swan 
lamp in our possession required 12 quart Bunsen cells to get a 
