the rods f.  The same shaft, M, opens and closes the valve, z, of the hopper, D, and thus regulates the entrance of the wash into the boiler.  The frame, E, receives its horizontal to and fro motion from the rod, l, which traverses a stuffing-box and is moved by a crank on an eccentric, m.  The material in powder derived from the evaporation of the wash is stored at the extremity of the apparatus into a lixiviating vessel, G, provided with a stirrer, H. The salts and other analogous matters are dissolved, and the residuum, which constitutes a carbonaceous mass, is forced out of the apparatus, while the solution passes directly to the refinery, where it is evaporated.

[Illustration:  Apparatus for the evaporation of organic liquids.]

In manufactories where no refining is done, the crude potassa in powder is pushed on to a prolongation of the apparatus which is cooled by means of water, and is removed from time to time with shovels by the workmen, so that the orifice of the boiler remains constantly covered externally by the mass, and that the air cannot re-enter the apparatus.

The gases disengaged during the operation pass into a cooler, where they condense into a liquid which contains ammonia and methylamine.  The non-condensable part of the gases is burned in the furnace of the manufactory.

* * * * *

IMPROVED LEVELING MACHINE.

In the American Court of the Inventions Exhibition, London, we find a leveling machine for sheet metals exhibited by Mr. J.W.  Britton, of Cleveland, Ohio, and which we illustrate.

This apparatus is intended to supersede the cold rolling of plates in order to take the buckle out of them.  The sheets are clamped in the jaws or grips shown, and the stretch is effected by means of a hydraulic ram connected directly to the nearest pair of jaws.  The power is obtained by means of a pair of pumps run through spur-gearing by the belt pulleys shown.  The action of the machine puts a strain on those parts of the plates which are not “bagged” or buckled, and this causes the surface to extend, the slack parts of the plate not being subject to the same stretching action.  The machine shown is designed to operate on sheet iron from No. 7 to No. 30 gauge, and up to 36 in. wide, the limit for length being 120 in.  About a dozen sheets can be operated on at once.  The machine appears to have met with considerable success in America, and has been used for mild steel, iron, galvanized or tinned sheets, copper, brass, and zinc.  The details of this machine are given in Figs. 1 to 8.  Figs. 1 and 2 are a plan and side elevation of the bed of the machine, showing the position of the hydraulic ram.  Fig. 3 shows the bars used for holding the back jaws in position, with the holes for adjusting to different lengths of the plates.  Fig. 4 is a back view and section of the crosshead and one of the bolts that connect the moving grip with the hydraulic ram.  Fig. 5 gives a plan and cross section of the back grip, and Fig. 6 is a back elevation of the same, with a front view and section of the gripping part.  Fig. 7 shows the gear by which the jaws are opened and closed.