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earth should by some means be caused to oocupy a larger 
space than they formerly did. In what manner could this 
tendency to expand be induced ? 
If we examine a common pebble, or stone, we must be 
aware that this is composed of various particles, which are 
held together by some mysterious power. If we direct our 
attention to a piece of granite, we must come to the same 
conclusion ; yet the granite, bulk for bulk, will probably 
weigh much more than the pebble. That power, or force, 
which attracted and held together the particles composing 
these two substances, must have acted with a diminished 
intensity, or for a shorter period, upon the particles com- 
posing the pebble than upon those composing the granite, 
or these pebbles would not be composed and arranged 
differently. What then is the power which has acted with 
a varying intensity on these substances ? By what means 
was it produced, how may it even now be working, or what 
are the laws regulating it ? Alas, we are reminded that 
science is but yet in its infancy, and that we live in the age 
of names. We speak about attraction, repulsion, electricity, 
magnetism, gravity, and other things, just as a Caffre might 
talk about the moon, the sun, the stars, &c. ; and we know 
as much of the actual components of these forces, or of 
their real nature, as does the savage of the celestial bodies. 
It is true that we know some of the effects of gravity, 
electricity, &c, just as the Caffre knows that the sun 
shines, and that the stars twinkle, otherwise we have our 
unknown, just as he has his. There is, then, some unknown, 
although named, power, which has caused various substances 
to differ in the approximation of their component parts. 
We find that the whole earth possesses a density equal 
to five and a half times that of water, consequently the 
particles of matter near the centre of the earth must be 
held to each other very closely. Is there any tendency on 
