8 ANNUAL OF SCIENTIFIC DISCOVERY. 



levers, a tappet is screwed, so that when the water gets too low it 

 presses the lower lever, and when too high it elevates the upper one ; 

 but in either case the safety-valve is lifted and the whistle sounded. 

 The same alarm is given when the steam is too strong. North Brit- 

 ish Mail. 



SAFETY-VALVE AND SIGNAL. A patent has been taken out for a 

 new arrangement of valve for the boilers of steam-engines, &c., which 

 not only performs the functions of an ordinary safety-valve, but gives 

 notice, by a loud signal, whenever the level of the water in the boiler 

 deviates from its proper limits, or in case of the safety-valve becoming 

 inoperative, by adhesion or any other cause. It consists of a standard, 

 which is tubular at the lower part ; on the top of this is a pulley, over 

 which works a chain, connected at one end to a float in the boiler, 

 while to the other hangs a balance-weight. From the bottom of the 

 standard projects an elbow-pipe, on the top of which is a chamber, 

 containing the safety-valve, and connected with a powerful steam- 

 whistle. The valve-rod is acted on by a weighted lever, the fulcrum 

 of which is on one side, and also by another acting in an opposite di- 

 rection. The ends of these levers are elbowed, and the rod from the 

 float within the boiler passes through them, having a tappet on it 

 midway between them, which, being either raised or depressed by 

 any fluctuation of water in the boiler, or in case of the float becoming 

 detached, acts against one of the lever ends, and thus raises the valve 

 and sounds the whistle. There is a graduated plate with an index- 

 hand on the pulley, acting as an indicator. When the steam attains too 

 high a pressure, the valve is acted on in the usual manner. Though 

 this patent is recent, this new apparatus has already been very exten- 

 sively introduced. London Mining Journal, Aug. 24. 



REGENERATIVE CONDENSER. 



AT the meeting of the Society of Arts, on May 15, Mr. C. W. 

 Siemens described a new condenser of his invention. It consists of a 

 series of copper-plates S 3 2 inch thick, 4| inches broad, and 2 feet long 

 each, which are piled together with two longitudinal flattened copper 

 wires, and the whole pile is screwed tightly together between the sides 

 of a rectangular closed vessel, which constitute the body of the con- 

 denser. The ends of the plates project through the top and bottom of 

 the vessel, and are made flush with its exterior surfaces ; after which 

 a ring of India-rubber is laid on, which is screwed down with a bon- 

 net. The flattened wires between the plates stand about three inches 

 apart, and form with them a large number of narrow passages, through 

 which the cold, condensed water flows in an upward direction ; while 

 their outer edges project into the vacuous space of the condenser, and 

 form the condensing surface. 



Encouraged by the success of this condenser, Mr. Siemens has di- 

 rected his attention to the achievement of a more important object, 

 which is to condense the steam in such a manner that the condensing 

 water issues into the hot well at boiling heat, and yet produces an 

 efficient vacuum within the working cylinder. This he has accom- 



