on by a moving power. In pointing out the advantages of tools, we
shall commence with some of the simplest.

11. To arrange twenty thousand needles thrown promiscuously
into a box, mixed and entangled in every possible direction, in
such a form that they shall be all parallel to each other, would,
at first sight, appear a most tedious occupation; in fact, if
each needle were to be separated individually, many hours must be
consumed in the process. Yet this is an operation which must be
performed many times in the manufacture of needles; and it is
accomplished in a few minutes by a very simple tool; nothing more
being requisite than a small flat tray of sheet iron, slightly
concave at the bottom. In this the needles are placed, and shaken
in a peculiar manner, by throwing them up a very little, and
giving at the same time a slight longitudinal motion to the tray.
The shape of the needles assists their arrangement; for if two
needles cross each other (unless, which is exceedingly
improbable, they happen to be precisely balanced), they will,
when they fall on the bottom of the tray, tend to place
themselves side by side, and the hollow form of the tray assists
this disposition. As they have no projection in any part to
impede this tendency, or to entangle each other, they are, by
continually shaking, arranged lengthwise, in three or four
minutes. The direction of the shake is now changed, the needles
are but little thrown up, but the tray is shaken endways; the
result of which is, that in a minute or two the needles which
were previously arranged endways become heaped up in a wall, with
their ends against the extremity of the tray. They are then
removed, by hundreds at a time, with a broad iron spatula, on
which they are retained by the forefinger of the left hand. As