sible silver and made it into a
precious mug again.

NATURAL AFFECTION OP METAL AND GAS

A man was waked up one night in a strange house by a noise he could not
understand. He wanted a light, and wanted it very much, but he had no
matches that would take fire by the heat of friction. He knew of many
other ways of starting a fire. If water gets to the cargo of lime in a
vessel it sets the ship on fire. It is of no use to try to put it out
by water, for it only makes more heat. He knew that dried alum and
sugar suitably mixed would burst into flame if exposed to the air; that
nitric acid and oil of turpentine would take fire if mixed; that flint
struck by steel would start fire enough to explode a powder magazine;
and that Elijah called down from heaven a kind of fire that burned
twelve "barrels" of water as easily as ordinary water puts out ordinary
fire. But he had none of these ways of lighting his candle at
hand--not even the last.

So he took a bit of potassium metal, bright as silver, out of a bottle
of naphtha, put it in the candle wick, touched it with a bit of
dripping ice, and so lighted his candle.

The potassium was so avaricious of oxygen that it decomposed the water
to get it. Indeed, it was a case of mutual affection. The oxygen
preferred the company of potassium to that of the hydrogen in the
water, and went to it even at the risk of being burned.

I was so interested in seeing a bit of silver-like metal and water take
fire as they touched that I forgot all about the occasion of the noise.

HINT HELP

Benjamin C. B. Tilghman, of Philadelphia, once went into the lighthouse
at Cape May, and, observing that the window glass was translucent
rather than transparent, asked the keeper why he put ground glass in
the windows. "We do not," said the keeper. "We put in the clear
glass, and the wind blows the sand against it and roughens the outer
surface like ground glass." The answer was to him like the falling
apple to Newton. He put on his thinking cap and went out. It was
better than the cap of Fortunatus to him. He thought, "If nature does
this, why cannot I make a fiercer blast, let sand trickle into it, and
so hurl a million little hammers at the glass, and grind it more
swiftly than we do on stones with a stream of wet sand added?"

He tried jets of steam and of air with sand, and found that he could
roughen a pane of glass almost instantly. By coating a part of the
glass w