The water necessary for the manufacture is forced by the pump, a, into
the reservoir, W, from whence it flows, through the pipes, r, into the
different machines. All the apparatus are set in motion by two
shaftings, q. The principal shaft makes two hundred revolutions per
minute, but the velocity of that of the pumps is but fifty
revolutions.--_Polytech. Journ., and Bull. Musee de l'Indust_.

* * * * *




A SIMPLE APPARATUS FOR DESCRIBING ELLIPSES.

By Prof. E.J. HALLOCK.


A very simple apparatus for describing an oval or ellipse may be
constructed by any apprentice or school boy as follows: Procure a
straight piece of wood about ¼ inch wide by 1/8 inch thick and 13 inches
long. Beginning ½ inch from the end, bore a row of small holes only
large enough for a darning needle to pass through and half an inch
apart. Mark the first one (at A) 0, the third 1, the fifth 2, and so on
to 12, so that the numbers represent the distance from O in inches. A
small slit may be made in the end of the ruler or strip of wood near A,
but a better plan is to attach a small clip on one side.

[Illustration: ELLIPSE INSTRUMENT.]