a a a a A ae Rt Sg 
On Electrotyping Operations of the U. S. Coast Survey. 313 
plates weighing 2,500 grains to the square foot failed, on account 
of the impossibility of observing Mr. Smee’s laws of electro-me- 
tallization for the time required. 
Bat after modifying the solutions of silver, and using a register 
battery, a plate could be made in thirty hours, perfectly flat, and 
possessing the mechanical qualities of hardness, elasticity, and 
malleability, in an eminent degree, and not costing over 16 cents 
per ounce for the making. wigs 
The perfectly flat plates admit of a very close approximation 
tothe zincs. Their size may therefore be increased to more 
than twice their former surface, as in the double arrangement, 
ller toR 
This experiment indicated that the batteries were not greatly 
by ordinary variations of temperature. Advantage was 
then taken of this development to secure a more perfect ventila- 
- Accordingly, a small room, to contain the battery, was 
Pattitioned off from the general apartment by a glass partition, 
and large outward openings made at the top and at the bottom of 
f room, to give a circulation of air for carrying off the battery 
IN size to the greatest useful extent, it was sought to increase 
by diminishing r, or the electrolytic resistance. It was sought 
i the conducting power of the electrolyte by adding 
fasily decomposable salts to it; but with no success. The ac- 
celerating effect of temperature being found, as above stated, to 
be confined chiefly to the decomposition cell, it was evident that 
by using the electrolyte alone, at a high temperature, a consider- 
able advantage might ensue. 
ONOOnD Senins, Vol. XV, No. 45.—May, 1853. 41 
