316 On Electrotyping Operations of the U. S. Coast Survey. 
to accomplish with large plates what is so easily done with med- 
als or small plates. ; 
It would, at first sight, appear that, by strengthening the solu- 
- tion of sulphate of copper, a more rapid supply of metal to the 
electrode would be obtained. Unfortunately, the effect of this 
.is to diminish the solvent capacity of the water in the solution 
for the sulphate formed on the positive electrode by the action 
of the transferred acid. The grand essential in electrolysis is 
liquidity. Thus, if the quantity of free water surrounding th 
positive electrode be small, this electrode is soon enveloped in 
a saturated solution, and the newly-formed salt remains undis- 
solved upon it. This salt, being a. non-conductor, virtually ex- 
cludes the electrode from the solution, and thus arrests the cur- 
rent, except when the efflux of saturated solution permits the 
salt to dissolve, and so reopens the passage for the current i 
irregular quantities. From this spasmodic action result plates of 
copper-sand, or sometimes copper as soft as lead. ti. 
By applying heat to the solution when this state of things 
exists, the solvent capacity of the water for the salt is increased, 
rapid diffusion takes place, the salt is carried to the negative elec- 
trode, and the exhausted water to the positive electrode ; the dor- 
mant batteries rush into uninterrupted action, and in a short time 
a plate is deposited, having all the hardness and elasticity of ham- 
mered or rolled copper. Smee’s conditions, then, seem to main- 
tain themselves, The electrotypist’s axiom of “ work slowly,” 
requires to be reversed into “the quicker the work, the better 
the quality.” 
Laboratory apparatus.—Ficure 1 is a plan of the coast survey 
electrotype laboratory. The glazed partition, b, 6, 0, 4, with 4 
r, d, separates the battery room from the general laboratory, 
and permits an easy inspection of the batteries, without exposure 
to their fumes. The laboratory floor is about six feet above the 
ground, and slopes inward from the sides towards the scuttle 
holes, h, h, h, h, arranged for discharging the waste liquids spilled 
upon the floor. To obviate the deleterious effects of working 
on a floor saturated with chemical agents, when any solutions 
are spilled, the floor is wel! flooded and brushed,, the water pas* 
ing off through the scuttle holes. There are four battery cells, 
placed as indicated, B, B, B, B.A rectangular India-rubber bag, 
a ‘ 
tallic tion unites all the zine plates of a cell, and another 
pe: all the silver plates ch cell can be used as an 1M : 
7; Of two, three, or four cells can be connected 10 stat 
secutive or simultaneous order, or all combined into two pairs af 
pres in consecutive or simultaneous order, or into one group 
ee and one of one. . The position of the vertical - 
