152 THE MEANING OF EVOLUTION 
who were willing to consider the question as open to 
human solution. This theory is known as La Place’s 
Nebular Hypothesis. When men began to study the 
heavenly bodies with the newly invented telescope, 
new ideas naturally sprang up. Among the objects 
which the glass disclosed were the nebulz, which are 
great clouds of fire mist, glowing masses of gas. They 
are scarcely visible to the naked eye, but are among 
the most interesting objects in the heavens. when seen 
through a telescope. The other suggestive heavenly 
body was our sister planet, Saturn. Besides having 
a full complement of moons, Saturn has around it, as 
distant as we would expect moons to be, three great 
rings. These look very much as if one’s hat, with 
an enormously wide brim, should have the connection 
between the rim and the hat broken out completely, 
but the rim should still float around the hat without 
touching it and should steadily revolve as it stood 
there. The rings of Saturn are not solid like the sug- 
gested hat rim. They are evidently made up of a 
great number of very small particles, each moving 
around the center of Saturn. But the great cloud of 
them is spread out flat. At the distance which Saturn 
is from the earth they look as if they made a solid 
sheet. Furthermore, they do not form, as it were, 
one continuous hat rim, but it is as if the rim were 
broken into three circular sections, each bigger than 
