562 
NATURE 
[April 13, 1882 
stained glass of the sides and bottom. The power of the 
lamps is ingeniously graduated by simply switching on or 
off more cells of the battery. 
Rumours of at least two other secondary batteries of 
great promise are in the air; but it is not yet known what 
these are, and they have not been exhibited in action 
yet before the public. They are doubtless modifications 
of some or other of the ordinary voltaic batteries by which 
their action can be conveniently reversed, and the altera- 
tion patented. For it is obvious that the old combination 
pure and simple cannot be patented for a new purpose, It 
must be changed in some way or other, though the essential 
action may be pretty much the same. 
The well-known Faure battery, which is exhibited by 
La Force et la Lumiére Company, in the Western 
Corridor, still continues to excite a good deal of debate 
amongst the Faurites and anti-Faurites. The construc- 
tion of the battery has already been described in NATURE, 
vol. xxv. p. 461 ; but some recent experiments by a group 
of French savants have contributed some further matter 
to the discussion of its merits, and as their results must 
be considered free from bias (which is perhaps more than 
can be said for all that has been written on the subject 
in this country) we shall give them in a condensed 
form. 
The experiments were made at the Conservatoire des 
Arts et Métiers, Paris, by MM. Allard, Le Blanc, Joubert, 
Potier, and Tresca, in continuation of experiments begun 
during the latter part of the Paris Electrical Exhibition. | 
The results were communicated by the authors to the 
French Academy of Sciences, on March 6. The battery 
consisted of thirty-five cells, of the new pattern, with 
plates rolled up together. 
grams, including the liquid. The lead plates were covered 
with minium to the amount of ro kilograms per square 
metre. The solution was formed of distilled water, mixed 
with one-tenth of its weight of pure sulphuric acid. It 
will be seen that the cells were in the most favourable 
condition for experiment. 
They were charged by a Siemens’ machine, of which 
the armature resistance was 0°27 ohms, and the resistance 
of the inducing magnets was 1945 ohms. The latter 
were excited by the current in a derived circuit from the 
main current in the armature. A species of voltameter 
was used to regulate this exerting current, so as to keep 
it between 2 and 3 amperes. 
The object of the experiments was to measure— 
1. The mechanical work expended in charging the | 
- battery. 
2. The quantity of electricity “stored” during the 
charge. 
3. The quantity of electricity yielded up during the 
discharge. 
4. The electrical work actually done during the dis- 
charge. 
It was also necessary to know, at each instant of the 
experiments, the electromotive force and the resistance 
of the battery ; and further, as the discharge should make 
itself through a series of Maxim incandescent lamps, to 
study the variation of the resistance, and the luminous 
power of these lamps, according to the intensity of the 
current. 
The mechanical work was measured by a totalising 
dynamometer, constructed for the French Society of Agri- 
culture by Messrs. Easton and Anderson, after the model 
belonging to the English Royal Society of Agriculture. 
The luminous intensity was measured by a Foucault 
photometer, such as was employed in the Exhibition 
experiments. As to the electric measures they were made 
by means of a Marcel Deprez galvanometer which mea- 
sured the total current generated, and sometimes the 
exciting current on the magnet; a Siemens’ electro- 
dynamometer which measured only the charging current; | 
and a dial electrometer arranged according to a plan of 
Each cell weighed 43°7 kilo- | 
M. Joubert, which gave the difference of potentials 
between the two poles of the battery. The indications of 
all the instruments were read off every quarter of an hour, 
sometimes at closer intervals. 
The following table gives the principal results :— 
TABLE I.—Charge of the Battery 
M 
Date Duration of Speed ofthe Indicated work E.M.F. of 
experiments. dynamo. inkilogrametres. the battery 
h. m. in volts. 
January 4 ... 5 30 1079 2,414,907 82°21 
eS ey O 1072 2,772,292 9t'o8 
jos?) 30) 1083 3,246,871 92°91 
Ps 7p 2 45 1085 1,135,728 92°06 
22 45 9,569,798 
Deduct 808,750 
8,761,048 
(The work deducted was lost in the transmission of the 
indicated power to the dynamo.) 
= Mean intensity He een ee 
Date. Deen Ge of charging exciting furnished by 
expermments: Paes current in _the battery 
h. m, amperes. in coulombs. 
January 4 5 30 10°93 2°46 216,4c0 
2 Abe 7°97 2°S 200, co 
” 6 7 30 7°94 2°33 214.300 
- 7 2 45 6°36 218 63,000 
22 45 694,500 
Electric work Electric work Electric work 
Date Duration of of the charge of excitation of the ring 
: experiments. in kilo- in kilo- in kilo- 
h. m. grammetres. grammetres. grammetres. 
January 4 ... 5 30 ... 1,814,600 ... 408,400 ... 94,400 
iy sigs fo) 1,947,100 676,300 ... 79,100 
Spe Oleen7230 2,028,800 596,100 ... 76,800 
A 7 2 45 591,600 202,800 ... 19,500 
22 45 6,382,100 1,883,600 269,800 
The same determinations have been made during the 
discharge, observing at the same time the power of 12 
Maxim lamps in a derived circuit. The light of a Carcel 
lamp was obtained from this experiment with an expendi- 
ture of 5°8 kilograms of electric work per second. 
The following table gives the results for the discharge 
of the battery :— 
TABLE I].—Déscharge of the Battery 
Mean External 
Duration of a f Tesistance Quantity of electric 
Date. the experi- thee ae f the electricity in work in 
ment. es ate TY current in coulombs. kilogram- 
h. m. in vo'ts. __ amperes. metres. 
Jani 7 yo 61 39 ... 16°128 ... 424,800 ... 2,608,000 
ane mar 2 20) 61 68 ... 16°235 ... 194,800 ... I,201,0CcO 
10 39 619,600 3,809,000 
The conclusion from these results is that between the 
quantity of electricity put into the battery (694,500 
coulombs) and that got out (6,196,000 coulombs) there is 
a difference of only 74,900 conlombs, corresponding to a 
proportional loss of 10 per cent. (0108). This refers, 
however, to the gvav/zty of electricity, not, be it remem- 
bered, to the power stored. The electric work during the 
entire discharge was 3,809,000 kilograms. The mechani- 
cal work expended was 9,570,000 kilograms, but only 
6,382,000 kilograms was really stored by the battery. It 
follows that the work recuperated or given back by the 
discharge of the battery is to that stored up, as 3,809,000 
is to 6,382,000: that is to say, about 60 per cent. of the 
energy of the current was rendered up by the battery. 
If we compare the work recuperated with that indicated 
by the dynamometer, the percentage given back is still 
less, namely, 40 per cent. 
This considerable loss of power, whilst the quantity of 
electricity is nearly the same in the charge and discharge, 
