64 FRAGMENTS OF SCIENCE. 



motion consequent upon the exertion of that force. This 

 motion must be figured fiv<t as a motion of translation, 

 and then as a motion of vibration, to which latter we 

 give the name of heat. For some time after the act of 

 combination this motion is so violent as to prevent the 

 molecules from. coming together, the water being main- 

 tained in a state of vapour. But as the vapour cools, 

 or in other words loses its motion, the molecules coalesce 

 to form a liquid. 



And now we approach a new and wonderful display 

 of force. As long as the substance remains in a liquid 

 or vaporous condition, the play of this force is altogether 

 masked and hidden. But as the heat is gradually 

 withdrawn, the molecules prepare for new arrangements 

 and combinations. Solid crystals of water are at length 

 formed, to which we give the familiar name of ice. Look- 

 ing at these beautiful edifices and their internal struc- 

 ture, the pondering mind has forced upon it the question, 

 How are they built up ? We have obtained clear con- 

 ceptions of polar force ; and we infer from our broken 

 magnet that polar force may be resident in the molecules 

 or smallest particles of matter, and that by the play of 

 this force structural arrangement is possible. What, in 

 relation *o our present question, is the natural action of a 

 mind furnished with this knowledge ? It is compelled to 

 transcend experience, and endow the atoms and mole- 

 cules of which crystals are built with definite poles whence 

 issue attractions and repulsions. In virtue of these forces 

 some poles are drawn together, while some retreat from 

 each other ; atom is added to atom, and molecule to mole* 

 cule, not boisterously or fortuitously, but silently and 

 symmetrically, and in accordance with laws more rigid 

 than those which guide a human builder when he places 

 his materials together. Imagine the bricks and stones 

 of this town of Dundee endowed with structural power. 



