Dec. 29, 1881] 
immediately manifest in polarisation effects, the plates 
becoming more uniformly and rapidly peroxidised when 
used as positive electrodes, and local action entirely dis- 
appearing. These mercury amalgamated plates at once 
give me an advance of other cells. I used them in many 
ways, constructing cells in which the positive plate was 
amalgamated, and the negative coated with red oxide, or 
with peroxide, produced by treating red oxide with dilute 
hydric nitrate till the brown precipitate of peroxide fell, 
the precipitate being washed and painted on the elec- 
trode. I also amalgamated the negative electrode simply. 
I found that in every way positive electrodes amalgamated 
produced the best results. I also made cells in which 
either peroxide or red oxide was formed into a porous 
conglomerate, using the conglomerates as electrodes, 
immersed in dilute hydric sulphate. I constructed cells 
with parallel plates, red oxide or peroxide being filled in 
between the plates; in this experiment red oxide is use- 
less and peroxide efficient. In all these experiments I 
succeeded in storing electricity to different extents. 
Having thoroughly satisfied myself that positive elec- 
trodes amalgamated with mercury were the best, I 
investigated the behaviour of various forms of negative 
electrode, having in view the conservation of the hydrogen ; 
this I thought to do by occluding the hydrogen in suitable 
electrodes, as spongy platinum or metallic palladium ; 
but as both these methods would be useless owing to 
expense I did not even experiment on them. 
I further thought of having negative electrodes, whose 
oxides should be soluble in the solution, and which could 
be redeposited from the solution, or of having metallic 
solutions from which metal could be deposited, the re- 
sulting solution being such that should, on the oxidation 
of the deposited metal, combine with the oxide and again 
form the original solution. 
I thought that success in this manner would result in a 
powerful and constant source of stored energy, the cell 
would not polarise itself during discharge, as is the case 
in both Planté and Faure cells; in these cells the peroxide 
formed by the discharge produces a contrary electro- 
motive force. 
Experimenting from this train of thought, the results I 
have obtained are such as to have an important practical 
bearing on the future of electric work. 
The experiments comprised amalgamated lead as a 
positive electrode with negative electrodes composed of 
either zinc, iron, or copper, in each case the solution 
between the electrodes being a salt of the metal com- 
posing the negative electrode. 
zinc was the solution; with iron, sulphate of iron; and 
with copper, sulphate of copper. In all these cases the 
results were not only far more powerful than with any 
form of cell I had previously devised, but also very con- 
stant, the polarisation lasting many times longer than in 
any other form of cell. The cell with zinc negative 
electrode I discarded, owing to the necessity there would 
be to keep the zinc plate amalgamated to prevent local 
action ; the iron negative electrode was set aside owing 
to the iron oxidising when the cell was not in use. The 
cell having a negative electruue of copper, a positive 
electrode of lead amalgamated with mercury and a solu- 
tion of cupric sulphate, I have adopted as a thoroughly 
economical, lasting, and practical form of storage reser- 
voir. The chemical changes in this cell are exceedingly 
interesting and beautiful, the cell being composed of a 
sheet of lead cleaned with dilute sulphuric acid and amal- 
gamated thoroughly with mercury, and a sheet of thin 
copper a little shorter ; the two sheets are perforated with 
a number of holes and then rolled in a spiral, separated 
by rubber bands cut every five inches, the holes in plates 
and cuts in rubber bands being to allow free circulation 
of the solution (the short plate being uppermost before 
rolling). This combination is immersed in a solution of 
cupric sulphate, and the amalgamated lead plate made 
With zinc, sulphate of | 
NATURE 
x 
199 
the positive electrode of a suitable source of electricity, the 
chemical action being that the oxygen of the decomposed 
solution combines with the lead, forming a perfectly even 
coating of the insoluble peroxide, the hydrogen replacing 
the copper of the solution, and the copper being deposited 
in the metallic state on the negative electrode. As the 
decomposition of the cupric sulphate proceeds the solu- 
tion gradually loses its azure blue colour, becoming more 
acid, and finally when the whole of the copper is de- 
posited, we have the solution colourless and transformed 
into hydric sulphate and water, the positive electrode 
peroxidised and copper deposited on the negative elec- 
trode. During discharge the peroxide is reduced and 
the copper element oxidised, the oxide combining with 
the acid and forming cupric sulphate, the solution re- 
turning to its original colour. This change of colour 
forms a beautiful means of telling when the cell is 
charged ; it is a veritable charging gauge. The power 
of this cell is very great and very constant; it can be 
made to last for hours, the time being dependent on the 
quantity of cupric sulphate decomposed. 
I have, by the decomposition and recomposition of one 
pint of cupric sulphate, obtained over two hours’ effective 
work in heating to a red heat one inch of No. 23 iron 
wire, the cell measuring internally 4 inches deep and 4 
inches diameter. : 
I constructed cells with free crystals of cupric sulphate 
suspended in the solution, and found that the presence 
of free crystals prevented the oxidation of the amalga- 
mated lead electrode, it being essential that the solution 
become slightly acid before the peroxide willform. The 
cell during charging gives out a peculiar rattling noise, 
which I consider due to the deposition of copper on the 
negative electrode altering the form of the spiral. 
A practical form of cell for storing purposes ought to 
be made, by fixing a series of amalgamated lead plates in 
a box in grooves, as in Cruikshank’s trough battery, 
filling the interval between the plates with solution of 
cupric sulphate, and passing a current through of suffi- 
cient tension to overcome the contrary electromotive 
force of the series, the positive sides of the plates being 
peroxidised and copper deposited on the negative sides. 
I have two boxes on this plan, each containing twenty- 
five plates, the total being equivalent to fifty cells. By 
this means batteries of great tension can be charged from 
thirty Bunsens. A number of twenty-five plate boxes 
can be coup'ed for quantity of charging, and for tension 
during discharge. Twenty such boxes, one foot square, 
internal measurement, will give in series a battery of 500 
pairs of one foot square plates. 
It will be seen from the foregoing that this method of 
conserving energy has a wide field before it, and as it 
will benefit fellow-workers in science, placing in their 
hands a means of experimenting with powerful electric 
currents, I give it without reservation, freely and 
untrammelled by patent rights, for their use. 
THE BISCHOFFSHEIM OBSERVATORY 
HIS observatory built at the expense of M. R. 
Bischoffsheim, the member of the French Lower 
House for Nice, is situated on Mont Gros, at an altitude of 
about 370 metres, and at a distance of eight English miles 
on the old Route de Ja Corniche, so well known and 
appreciated by the tourists travelling by road from Nice 
to Genoa. M. Celora, Milan astronomer, Commander 
Bahat of the French Staff, and M. Perrotin,the present 
director of the Bischoffsheim Observatory, have ascertained 
electrically and astronomically, the longitude and latitude 
of the new establishment which has been connected with 
Paris and Milan, by unquestionable observations. 
The buildings have been constructed under the direct 
supervision of M. Garnier, the architect of the Paris 
