Why does the ice float?--think of that, and philosophise.
Because the ice is larger than the quantity of water which can produce it;
and therefore the ice weighs the lighter, and the water is the heavier.
To return now to the action of heat on water. See what a stream of vapour
is issuing from this tin vessel! You observe, we must have made it quite
full of steam to have it sent out in that great quantity. And now, as we
can convert the water into steam by heat, we convert it back into liquid
water by the application of cold. And if we take a glass, or any other
cold thing, and hold it over this steam, see how soon it gets damp with
water; it will condense it until the glass is warm--it condenses the water
which is now running down the sides of it. I have here another experiment
to shew the condensation of water from a vaporous state back into a liquid
state, in the same way as the vapour, one of the products of the candle,
was condensed against the bottom of the dish, and obtained in the form of
water; and to shew you how truly and thoroughly these changes take place,
I will take this tin flask, which is now full of steam, and close the top.
We shall see what takes place when we cause this water or steam to return
back to the fluid state by pouring some cold water on the outside.
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