13 
Who amongst the thousands inhabiting those regions of the 
earth, where water is rendered solid by the reduction of the 
winter temperature, but has noticed the air bubbles enclosed in 
the transparent ice ? None ot these thousands discovered a great 
fact in this until Professor Henry was led to examine it. The 
result of that investigation has been the discovery of the 
remarkable truth, that water in the process of eongcllation 
actually squeezes out everything it may hold in solution, and 
becomes far more pure than it can be rendered by any other 
means. If water holding air, colouring matter, or saline bodies 
in solution is, while being frozen, kept in a state of slight agita- 
tion, the air, the colour, and the salt are all rejected alike, and 
a tasteless, colourless, transparent ice remains. It is curious to 
see how near a great truth men often are, and how long they 
allow it to escape them. It has been the constant practice of 
the Russian nobles to place their wines in ice until they were 
frozen, for the purpose of obtaining the small quantity of ardent 
spirit left in the centre of the mass. The water of the wine in 
freezing liberated the alcohol and flavouring matter, and a 
pungent cordial was thus obtained. 
Ice thus free of air, if melted out of contact with the atmo- 
sphere, may be heated to nearly 300°, when, instead of boiling, 
it explodes. IIow nicely balanced are the conditions of all 
things in nature. We now learn that if water was not the all 
absorbing body which it is, it would be as dangerous to expose it 
to heat as gunpowder or any other explosive compound. This 
interesting discovery promises to throw some light upon many 
of the steam-boiler explosions, which wall form a subject of 
inquiry in the present course. As another illustration of the 
manner in which we have, from the defective character of our 
education, allowed phenomena continually presenting themselves 
to us to escape attention, look to the investigations of Boutigny. 
That drops of water thrown upon hot iron arrange themselves 
into spheroids, and move about with a peculiar internal motion, 
is nothing new. Yet who amongst us suspected that these 
dancing drops were telling a story to man which will in all 
probability completely change our ideas of the properties of 
heat ? 
