MECHANICS AND USEFUL AKTS. 67 



works rapidly. Whether it be steam or water which comes from the boiler, 

 it is alike discharged into a feed heater, together Avith the additional water 

 required, and is finally pumped back into the boiler at a temperature nearly 

 up to the boiling point. 



Holly s Elliptic Rotary Pump and Steam Engine. In this invention the 

 principle is that of two gear-Avheels meshing into each other within a tight 

 case, and bringing up at each revolution as much water as can be contained 

 in the cavities between the teeth ; but there are several points in which it 

 differs from this ancient device, one of Avhich is the giving of the gear-wheels 

 substantially an elliptic form, the points, so to speak, of one touching against 

 the flat or rather the Iwllow sides of the other, and vice versa. The Avhole is 

 ingeniously and carefully packed, especially Avhen to be used as a steam 

 engine, and a very novel idea is adopted in working the steam condensingly 

 Avhen the steam engine and pump are intimately connected. For this pur- 

 pose the exhaust steam, instead of being discharged into the atmosphere, is 

 turned into the suction-pipe, where it is instantly condensed, and all the suc- 

 tion or vacuum there existing is felt on the exhaust side of the pistons to aid 

 the working of the engine. 



IMPROVEMENTS IX GRATES AXD FURNACES. 



Xcel Fire G-rate. By B. F. Foering. of Philadelphia, Pa. Certain kinds 

 of anthracite coal, when burned in stoves, produce a clinker, or laA~a, that 

 adheres to the sides of the stove, or fills the interior, and prevents good com- 

 bustion. The clinker generally forms at the lower part of the fire. If there 

 were any means of holding up the fire so that the ash grate could be 

 removed, the clinker stuff might all be easily taken out from below at plea- 

 sure. At present, the clinker cannot be weh 1 removed until the fire is 

 extinguished, and it is then hard, flinty, and liable to injure the lining of the 

 stove in being broken off. This improvement is intended to remedy the 

 above defects. Apertures are made in one side of the stove, just above 

 where the clinkers form, and through these holes suitable bars are intro- 

 duced ; when the bars are pushed in they form a temporary grating, which 

 supports the fire while the ash grate below is taken out for the removal of 

 the clinker refuse. 



Cramptoris Improved Furnace. T. R. Crampton, of London, has pa- 

 tented an improvement hi locomotive and other boiler furnaces, which con- 

 sists in employing a series of flat bars arranged transversely in a furnace of a 

 steam boiler, one bar below another, and somewhat forward of each other, 

 thus producing a shelving grating, with spaces for the passage of air horizon- 

 tally between the bars. At the lower part of such series of shelving bars is 

 a series of ordinary fire bars, which receive the well ignited fuel descending- 

 down the shelving bars, and which are so connected with an axis as to allow 

 fire to be dropped upon them when desired. 



Improvement in Smelting Furnaces. A patent has been taken out in 

 England, by Mr. A. Jenkins, for the following improvements in the above- 

 named furnaces : 



The principal feature in the improved reverberatory furnace is, that one fire 



