olor it with a
little blueing or red ink. Into the glass put two or three
glass tubes, open at both ends, and with bores of different
sizes. (One of these tubes should be so-called thermometer
tubing, with about 1 mm. bore.) Watch the colored water and
see in which of the tubes it is pulled highest.

EXPERIMENT 14. Put a clean washed lamp wick into the glass of
colored water and watch to see if the water is pulled up the
wick. Now let the upper end of the wick hang over the side of
the glass all night. Put an empty glass under the end that is
hanging out. The next morning see what has happened.

[Illustration: FIG. 19. Will the water be drawn up higher in the fine
glass tube or in a tube with a larger opening?]

[Illustration: FIG. 20. The water rises through the lamp wick by
capillary attraction.]

The space between the threads of the wick, and especially the still
finer spaces between the fibers that make up the threads, act like
fine tubes and the liquid rises in them just as it did in the fine
glass tube. Wherever there are fine spaces between the particles of
anything, as there are in a lump of sugar, a towel, a blotter, a wick,
and hundreds of other things, these spaces act like fine tubes and the
liquid goes into them. The force that causes the liquid to move along
fine tubes or openings is called _capillary attraction_.

Capillary attraction--this tendency of liquids to go into fine
tubes--is caused by the same force that makes things cling to each
other (adhesion), and that makes things hold together (cohesion). The
next two sections tell about these two forces; so you will understand
the cause of capillary attraction more thoroughly after reading them.
But you should know capillary attraction when you see it now, and know
how to use it. The following questions will show whether or not you
do:

_APPLICATION 10._ Suppose you have spilled some milk on a
carpet, and that you have at hand wet tea leaves, dry corn
meal, some torn bits of a glossy magazine cover, and a piece
of new cloth the pores of which are stopped up with starch.
Which would be the best to use in taking up the milk?

_APPLICATION 11._ A boy spattered some candle grease on his
coat. His aunt told him to lay a blotter on the candle grease
and to press a hot iron on the blotter, or to put the blotter
under his coat and the iron on top of the candle grease,--he