Fig. 50. SPIRAL BATTERY, OR HARE'S DEFLAGRATOR.
Battery, Spiral.
A battery whose plates of thin zinc and copper are wound into a spiral
so as to be very close, but not touching. Dilute sulphuric acid is the
excitant. It is now practically obsolete.
Synonyms--Calorimeter--Hare's Deflagrator.
Battery, Split.
A battery of a number of voltaic cells, connected in series, with their
central portion grounded or connected to earth. This gives the ends of
opposite potentials from the earth, and of difference therefrom equal to
the product of one-half of the number of cells employed, multiplied by
their individual voltage.
Battery Solutions, Chromic Acid.
A number of formulae have been proposed for these solutions. (See
Electropoion Fluid--Kookogey's Solution--Poggendorff's Solution--
Trouvé's Solution--Delaurier's Solution--Chutaux's Solution--Dronier's
Salt--Tissandier's Solution.)
Battery, Trough.
A battery whose elements are contained in a trough, which is divided by
cross-partitions so as to represent cups. A favorite wood for the trough
is teak, which is divided by glass or slate partitions. Marine glue or
other form of cement is used to make the joints tight. For porous cup
divisions plates of porous porcelain or pottery are placed across,
alternating with the impervious slate partitions.
Battery, Trouvé's Blotting Paper.
A battery of the Daniell type in which the solutions are retained by
blotting paper. A considerable thickness of blotting paper lies between
the two plates. The upper half of the thickness of the blotting paper is
saturated with a solution of zinc sulphate, on which the zinc plate
rests.
The lower half of the paper is saturated with copper sulphate solution,
and this rests upon the copper plate.
Fig. 51. TROUVÉ'S BLOTTING PAPER BATTERY.