A DROP OF WATER. 
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up more room than water, and that this is the reason 
why our water-pipes burst in severe frosts; for as the 
water freezes it expands with great force, and the pipe 
is cracked, and then when the thaw conies on, and 
the water melts again, it -pours through the crack it 
has made. 
It is not difficult to understand why ice should take 
more room; for we know that if we were to try to 
arrange bricks end to end in star-like shapes, we must 
FIG. 24. Water flowers in melting ice. TYNDALL. 
leave some spaces between, and could not pack them 
so closely as if they lay side by side. And so, when 
this giant force of crystallization constrains the atoms 
of frozen water to grow into star-like forms, the solid 
mass must fill more room than the liquid water, and 
when the star melts, this space reveals itself to us 
in the bright spot of the centre. 
We have now seen our drop of water under all its 
various forms of invisible gas, visible steam, cloud, 
