152 TWO WAYS TO GO TO SEA:

grows hotter and hotter; so they can tell
by the color how hot it is.”

“That is curious,” said Rollo.

‘So John had a box of screws in a little
stand before him, and was brightening them
upon an emery-wheel. Do you know what
an emery-wheel is?”

“No,” said Rollo and Lucy, together.

“Tt is a small wheel cut out of a board,
which goes round very fast by water. It
has leather all around the edge, and emery
on the leather, and they touch the screws on
this, and the wheel, going round very fast,
polishes the part of the screw which touches,
and makes it very bright. John would take
up a handful of screws in one hand, and then
take them, one by one, in the other, and just
touch them to the emery-wheel, and brighten
a little spot’ upon each ; and then drop them
into another box. After he had got them
all brightened, he took them to a bench, and
began to temper them.”

“ How?’ said Rollo.

“Why, he had a little pan of charcoal,
and over it a shallow iron basin, half full of
sand, which of course was hot. He would