Electrostatic Stress.
The stress produced upon a transparent medium in an electrostatic field
of force by which it acquires double refracting or polarizing properties
as regards the action of such medium upon light. (See Electrostatic
Refraction.)
Electro-therapeutics or Therapy.
The science treating of the effects of electricity upon the animal
system in the treatment and diagnosis of disease.
Electrotonus.
An altered condition of functional activity occurring in a nerve
subjected to the passage of an electric current. If the activity is
decreased, which occurs near the anode, the state is one of
anelectrotonus, if the activity is increased which occurs near the
kathode the condition is one of kathelectrotonus.
Electrotype.
The reproduction of a form of type or of an engraving or of the like by
electroplating, for printing purposes. The form of type is pressed upon
a surface of wax contained in a shallow box. The wax is mixed with
plumbago, and if necessary some more is dusted and brushed over its
surface and some iron dust is sprinkled over it also. A matrix or
impression of the type is thus obtained, on which copper is deposited by
electroplating, q. v.
Element, Chemical.
The original forms of matter that cannot be separated into constituents
by any known process. They are about seventy in number. Some of the
rarer ones are being added to or cancelled with the progress of chemical
discovery. For their electric relations see Electro-chemical
Equivalents--Electro-chemical Series.
The elements in entering into combination satisfy chemical affinity and
liberate energy, which may take the form of electric energy as in the
galvanic battery, or of heat energy, as in the combustion of carbon or
magnesium. Therefore an uncombined element is the seat of potential
energy. (See Energy, Potential.) In combining the elements always
combine in definite proportions. A series of numbers, one being proper
to each element which denote the smallest common multipliers of these
proportions, are called equivalents. Taking the theory of valency into
consideration the product of the equivalents by the valencies gives the
atomic weights.