ponty, until the soft mass drooped down and touched the bottom of the
inkstand, to which it adhered. The man and the boy held the lump a
moment between them; then, at a word of command, the boy shouldered
his ponty, like a very large staff with a very small bundle on the
end of it, and set out to travel. As he ran in one direction, into a
work-room, the man backed off in the other, the glowing lump stretching
between them, like some miraculous kind of spruce gum. In a minute
they were seventy or eighty feet apart, with a gleaming cord of glass,
smaller than a pipe-stem, sagging between them. This was presently
lowered, laid out at its full length upon the ground, and broken from
what was left of the lump at the ends.
Even the Doctor, who had hitherto said little,
now expressed his astonishment and admiration, exclaiming, "It is
marvellous! it is truly marvellous!"
"Of course," said the gaffer, "the bore stretches
with the tube, and keeps its flattened shape. So does the stripe."
"But what keeps the tube of uniform size? Why
don't it break?" said Lawrence.
"The reason is this. As the glass runs out
thin, it cools, and stops stretching, while it continues to draw out
the soft glass from the thicker parts at the ends. If we wish to make
a small tube, we stretch it quick, without giving it much time to cool.
To make a large tube, we stretch slower. Here is a piece of a barometer
tubing, stretched in the same way; so is
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