48 
POPULAR SCIENCE REVIEW. 
Tlius it is that man, to some extent the servant, hut hoping 
to become more the master of nature, is daily striving to 
acquire a greater knowledge of the workings of natural 
forces, and to apply those forces to human benefit ; he first 
becomes the obedient disciple of nature, in order that he 
may ultimately become its director ; and so great a degree 
of success has already resulted from this course, that we 
are justified in expecting that, at some future time, science 
will extend its helping- hand to all trades and manufactures, 
and that ultimately scientific principles will be universally 
recognized as the great “ regulators of productive industry.” 
EXPLANATION OF PLATE V. 
Fig. I represents what is termed a “ single-cell electrotype apparatus.” It 
consists of an outer vessel of glass or stoneware nearly filled with 
the depositing solution of silver or copper, as the case may be ; 
standing within it is a narrow, deep vessel of unglazed or porous 
earthenware, containing a plate of amalgamated zinc, and about 
three-fourths filled with dilute sulphuric acid. The article to be 
coated is connected by a clean copper wire and brass screw with 
the zinc plate, as shown in the engraving, and is immersed in the 
metallic solution. 
Fig. 2 represents the actual apparatus for electro-plating, as at present em- 
ployed. It consists of two parts, the battery A, and depositing 
trough or vat B ; Z is the zinc plate, and C C the two copper plates 
of the battery, and S is- the silver-dissolving plate in the metallic 
sc’ution : the arrows represent the direction of the electric current. 
Fig. 3 represents the mode of connecting several battery-cells in series when 
additional electric power is reepured : the battery-plates in this 
sketch are represented as being composed of zinc, Z, and silver, S, 
instead of zinc and copper ; the zinc of the first cell being con- 
nected by a copper wire with the silver of the second ; the zinc of 
the second with the silver of the third ; and so on. 
