MICROPHONE, MEGAPHONE, TASIMETER, BATHOMETER, ANEMOMETER,
CHRONOMETER.


What is Attraction?

By attraction is meant that property or quality in the particles of
bodies which makes them tend toward each other.


Are there several kinds of attraction?

Yes. Attraction has received different names, according to the
circumstances under which it acts: The force which keeps the particles
of matter together to form bodies or masses, is called attraction of
_cohesion_; that which makes bodies stick together only on their
surfaces, is called _adhesion_; that which inclines different masses
toward each other, as the earth and the heavenly bodies, is called
_gravitation_; that which forces the particles of substances of
different kinds to unite, is known under the name of _chemical
attraction_; that which causes the needle of the compass to point
constantly toward the poles of the earth, is _magnetic attraction_;
that which is excited by friction in certain substances, is known as
_electrical attraction_.


How do you know that attraction exists through the whole universe?

This great universal law was first discovered by Sir Isaac Newton. The
sun and planets and other heavenly bodies are only guided in their