ment with on the earth.

[Footnote 33: _Popular Lectures_, Vol. II.]

ART. 88. _The Sun an Electro-magnet._--If the sun is an electro-magnet,
as stated in the previous article, then it is necessary for us to apply
the phenomena of magnetism to it in order to ascertain what effect such
application will have on the solar system as a whole.

[Illustration: Fig: 17.]

The first thing that we will look at is the magnetic field which is
always associated with every magnet. The magnetic field may be defined
as that region or space around every magnet in which the magnetic force
acts or is in operation. An illustration of a magnetic field may easily
be obtained by taking a bar magnet and bringing near to it a magnetized
needle, when it will be found that the needle will set itself in various
positions relative to the magnet, on account of the lines of force which
exist in the field. Thus let _A_ _B_ (Fig. 17) be a bar magnet with its
North pole at point _A_ and South pole at point _B_. If a number of
freely suspended needles be hung above it, as shown in the figure, they
assume the positions indicated there. It will be seen that at the North
and South poles the needles hang vertical, while midway between the two
poles there is no dip of the needle, as it is parallel to the bar
magnet; while between the place of no dip and the place of vertical dip,
which is directly over each pole, the dip gradually changes, becoming
more and more vertical as it gets nearer to the pole. If the bar magnet
be a strong one, then its magnetic field will be manifested at a great
distance; and any magnetized needle brought into the field will be,
affected by the same, and will tend to set itself along the lines of
force.

As already stated in Art. 80, it was Faraday who originated the term
"Lines of Force," and gave to the world some idea of the motions of the
aetherial medium, which plays so important a part in electro-magnetic
phenomena. A visible manifestation of these lines of force which gather
round every magnet may be made by strewing iron filings over a piece of
glass, underneath which are several bar magnets, when it will be found
that the iron filings will set themselves in well-defined lines or
curves, which Faraday termed "Lines of Force."

[Illustration: Fig: 18.]

As the bar magnets are placed in different positions, North pole to
North pole, or North to South, and so on, the iron filings will change
the figures assumed, indic