CXIII
vessel, in which we pour strong nitric acid, and finally a thin
plate of platinum is immersed in the nitric acid. The positive
current passes through the liquid from the platinum to the zinc.
4) Lectanche's battery. The outer vessel contains a solu
tion of sal-ammoniac, in which the positive metal zinc is immersed
in the porous pot inside we have a mixture of coke and peroxide
of manganese, which encloses the negative rod of carbon. This
simple and powerful battery is coming into use for telegraphs.
440.
§ 284. 6) Effects of the electric stream. They may be
classified just as those of the Leyden jar.
1. Physiological effects consist of shocks and violent con
tractions in the muscles of animal bodies which are not instan
taneous as in the case of a Leyden jar, but succeed each other
with rapidity (on account of the continuous slow of electricity).
In the visual nerve the sensation of light is caused, in the
gustatory nerves the sensation of taste; positive electricity ap
plied on the tongue gives a sourish, negative an alkaline taste
(in consequence of the chemical decomposition of the saliva).
The sensation of light we may produce by holding one wire in
the moistened hand and touching with the other the wetted
forehead (see § 228, subjective phenomena of light). The
same will take place, if we apply a silver spoon to one side and
a stripe of zinc to the other side of our gum. By the same
bodies also the sensation of taste may be caused.
11. Physical effects.
§ 285. a) Heating effects: wires of lead, tin, zinc, copper,
gold, silver, iron, platinum melt and volatilize with differently
coloured sparks. Thus by a voltaic current the firing of mines,
blasting operations and the burning out of wounds may be
carried out. 441.
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