cause a precipitate in case the slightest trace of an alkali be present.

* * * * *




POWER HAMMERS WITH MOVABLE FULCRUM.

[Footnote: Paper read before the Institution of Mechanical
Engineers.--_Engineering_.]

By DANIEL LONGWORTH, of London.


The movable-fulcrum power hammer was designed by the writer about five
and a half years ago, to meet a want in the market for a power hammer
which, while under the complete control of only one workman, could
produce blows of varying forces without alteration in the rapidity with
which they were given. It was also necessary that the vibration and
shock of the hammer head should not be transmitted to the driving
mechanism, and that the latter should be free from noise and liability
to derangement. The various uses to which the movable fulcrum hammers
have been put, and their success in working[1]--as well as the
importance of the general subject which includes them, namely, the
substitution of stored power for human effort--form the author's excuse
for now occupying the time of the meeting.

[Footnote 1: The hammers have been for some years used by A. Bamlett, of
Thirsk; the American Tool Company, of Antwerp; Messrs. W.&T. Avery, of