ELECTRIC LIGHT APPLIED TO MICROSCOPICAL RESEARCH. 143 


The Tommasi battery prepared and charged as has just been 
explained will work for ten hours. After each such period it is 
emptied by means of caoutchouc tubes fixed upon the exterior jar 
of the last cell in each series and leading to a collector for the 
waste water. ‘The zincs are then left dry and are not being con- 
sumed save while the battery is working. 
With regard to the renewal of the mixture and of the zinc it is 
sufficient every other day to refill anew the glass bottle, and place 
a ring of zinc in each jar when it is necessary. 
The battery is never taken down, To keep it in proper condition 
it is enough to fill the central box with water once a month, open 
all the taps, lower the caoutchouc tubes into the collector, and let 
all run until the supply is exhausted. 
This monthly precaution is sufficient to clean out the pile per- 
fectly, and free it from whatever residues may be left there. 
We may see that the management of this pile is very easy, and— 
what is most important—its employment is very economical, taking 
into consideration the results obtained. For some time we have 
had such a battery of fifty cells, and are very well pleased with its 
performance. 
But we may remark that when illumination for the microscope 
is the only thing to be considered there is no need of such an 
apparatus; with ten cells one has more than is necessary, as we 
shall soon shew, to illumine the new microscope lamps of Mr. 
Swan. 
LEVSTORACE Or ELECTRICITY, 
The electricity produced by the battery or by the machine should 
not be employed directly it is obtained. It may even be stored 
for several days in secondary batteries or accumulators as they are 
really called. These apparatus, devised by M. Gaston Plante, 
have been perfected by numerous inventors. One of the most 
practicable systems is that of M. Faure. We represent, page 144, the 
accumulator of this system as it is manufactured by M. E. Reynier. 
It consists essentially of two leaden plates covered with a thick 
coating of red lead, separate, rolled up in flannel and plunged into 
a glass cylinder, tightly closed, and containing water acidulated to 
To p.c. with sulphuric acid. 
The accumulators allow the utilization of all the force of the 
primary battery in storing the electricity produced, both when it 1s 
not being used and afterwards in exhausting the liquids placed in 
Ls 
We have coupled a series of such accumulators which remain 
constantly in the current; when stopping work for the night we 
connect all the accumulators with the battery, and they remain 
thus till the next evening. 
| 
: 

