42 ANNUAL OF SCIENTIFIC DISCOVERY. 



is, of course, already clearly told by the indicator, and many are the valvular 

 defects and derangements which the mechanical engineer has proved and 

 remedied by the help of this little instrument. Now there is no reason why 

 the "indicator" system should not find equally as good an application with 

 reference to the real source of the power the steam boiler. At present we 

 put coals into the furnace, and pour water into the boiling chamber for con- 

 version into steam, whilst we have no satisfactory return to show whether 

 each pound of fuel does or docs not produce the amount of mechanical 

 effect which is exigible from it. But such an explanatory statement can 

 now be obtained in a very simple and accurate manner, by mounting guard 

 upon the water feed-pipe of the boiler with a good water meter. Each 

 boiler must, of course, have its own special meter, so that, however many 

 boilers there may be working in concert, the truth is always told as to the 

 performances of every individual one. 



IMPROVEMENTS IN STEAM BOILERS. 



George Jackson, of England, has patented " a new or improved steam 

 boiler, to be heated by the waste heat of puddling or mill furnaces." The 

 boiler is of cylindrical form, and is terminated by hemispherical or nearly 

 hemispherical ends. The boiler is set in its casing of brickwork in a verti- 

 cal position, and the hot air and the fire are made to circulate about and 

 through the said boiler in the following manner : " The fire is conducted 

 from a couple of puddling or mill furnaces through two flues, and delivered 

 near the bottom of the boiler. After being made to circulate about the 

 vertical sides of the cylindrical boiler, the said fire enters a horizontal flue 

 passing through the boiler at a point a little higher than its middle. The 

 fire enters the horizontal flue at both ends, and passes up a vertical flue or 

 chimney, which is situated in the axis of the boiler, and opens into the hori- 

 zontal flue. A damper is situated at each end of the horizontal flue, and 

 by the dampers the draught may be regulated. That part of the vertical 

 chimney which is within the boiler is surrounded with an air space, that is 

 to say, there is an annular layer of air between the chimney and the boiler, 

 so that the chimney is isolated, so far as its temperature is concerned, from 

 the upper part of the boiler. The isolating air space descends to a point 

 below the water level of the boiler, and any danger which would otherwise 



J o 



attend the over-heating of the chimney is avoided." 



}Vrlf)ld's Improvements in Manufacturing Boilers. In the ordinary manu- 

 facture of cylindrical boilers, the plates are so arranged that the rive ted joints 

 run in lines parallel to the axis of the boiler, and in planes perpendicular 

 to the axis ; or, in other words, the joints run in the direction of the length 

 of the boiler, and at right angles to it. The joints running parallel to the 

 axis of the boiler, or the longitudinal joints, it is well known, are subjected 

 to a greater strain than those crossing them at right angles and running 

 round in planes perpendicular to the axis, and consequently the longitudinal 

 jointing is the weakest, and the part of the boiler first to give way under 

 great pressure. 



In order to remove this defect, Mr. E. T. Wright, of Wolverhampton, 



