The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million — John Stuart Mill — John Shaqi
The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million
John Stuart Mill · en
634. _What are magnetic bodies?_
Magnetic bodies are those that exhibit phenomena which show that
they are under the influence of _terrestrial electricity_, and which
indicate the direction of the _poles_, or _extreme points_, _of
magnetic force_.
635. _What is Galvanism?_
Galvanism is the action of _electricity upon animal bodies_, and is so
called from the name of its first discoverer, Galvani.
636. _What is Voltaic electricity?_
Voltaic electricity is the electricity that is developed during
_chemical changes_, and is so called after Volta, who enlarged upon the
theory of Galvani.
637. _What are the differences between mechanical, or frictional
electricity, Voltaic electricity, Galvanism, and magnetism?_
_Frictional_ electricity is electricity _suddenly_ liberated under the
effects of the _motion_, or the mechanical disturbance of bodies.
_Voltaic_ electricity is a _steady flow_ of an electric current,
arising from the _gradual changes_ of _chemical_ phenomena.
_Galvanism_ and _Voltaism_ are almost _identical_, since the latter
is founded upon, and is a development of, the former. But the term
_Galvanism_ is frequently used when speaking of the development of
electricity in _animal bodies_.
_Magnetism_ is the electricity of the _earth_, and is understood to
imply the _fixed electricity of terrestrial bodies_.
[Verse: "And I heard as it were the voice of a great multitude, and
as the voice of many waters, and as the voice of mighty thunderings,
saying Alleluia: for the Lord God omnipotent reigneth."--REV. XIX.]
Man knows not _what electricity is_; yet, by an attentive
observance of its _effects_, he avails himself of the power
existing in an unknown source, and produces marvellous results.
When the Grecian philosopher, Thales, sat rubbing a piece of
amber, and watching the attraction of small particles of matter
to its surface, he little knew of the mighty power that was then
whispering to him its offer to serve mankind. And when Franklin,
with the aid of a boy's plaything, drew down an electric current
from the clouds, and caught a spark upon the knuckles of his hand,
_even he_ little conjectured that the time was so near when that
strange element, which sent its messenger to him along the string
of a kite, would become one of man's most submissive servants.