ON THE ANTHRACITE COAL AND COAL-FIELD OF SOUTH WALES. 227 



and extraordinary heat evolved by stone coal under the influence of arti- 

 ficial draught, requires some means for the protection of the bars. I also 

 venture to think that, as described by Dr. Percy in the extract from his 

 work which I have already given, the property of decrepitation may, as 

 he says, so seriously check the passage of air through a furnace that the 

 desirability of conveying the draught by means of the bars themselves, to 

 all parts of the fire, is very apparent. 



With the view of meeting the several difficulties I have endeavoured 

 to describe, Mr. R. W. Perkins (than whom no better authority upon 

 matters connected with anthracite exists), in connection with Mr. F. H. 

 Perkins and Mr. Joseph Williams, took out a patent in November 1876, 

 entitled ' Improvements in and relating to furnaces for burning anthra- 

 cite and other fuel,' the main features of which consisted in the employ- 

 ment of hollow perforated bars, through which the blast is forced by a fan, 

 steam-jet, or other artificial means. In this way combustion is enormously 

 accelerated, and at the same time the bars are kejDt perfectly cool by the 

 current of cold air passing through them. I have myself seen a piece of 

 paper inserted within a bar when the fire was at its hottest, and remain- 

 ing unsinged for a very considerable time. With this appliance Mr, 

 Perkins instituted a series of trials at the foundry of Mr. T. W. Williams, 

 of Swansea, and he has favoured me with the following results : — 



Duration of experiment, five hours, with ordinary furnace and chimney 

 draught, which was good ; coal used, ' Birch Grove Graigola ' — 



Evaporated 706 lbs. water to lib. of coal, and 672 lbs. water per 

 hour. 

 Coal used, 'Powell's Duffryn' — 



Evaporated 7'S3 lbs. Avater to 1 lb. of coal, and 745 lbs. water per 

 hour. 



The bars with this coal were much burnt. 



With Perkins's bars, but no blast ; coal used, anthracite — 



Evaporated 7-94 lbs. water to 1 lb. of coal, and 594 lbs. water per 

 hour. 



Bars slightly heated, but not damaged. 



With a fan and Perkins's furnace ; coal used, anthracite, Hendre- 

 forgan ' Big Vein ' — 



Evaporated 7'981bs. water to lib. of coal, and 960 lbs. water per 

 hour. 

 Deducting steam used for fan, the result was 7-92 and 952, the 

 bars remaining perfectly uninjured. 



The above experiments were authenticated by Mr. J. F. Flanneiy, 

 C.B., who was present on behalf of Mr. E. J. Eeed, M.P. 



A further series of experiments was made with Korting's steam-jet 

 blower and Perkins's furnace, with the following results : — 



Blower used No. 1 ; diameter of steam nozzle |th of an inch, full 

 open ; coal, Hendreforgan anthracite ; duration of experiment 2 hours 

 15 minutes- — • 



Evaporated 814 lbs. water to 1 lb. of coal, and 912-22 lbs. water per 

 hour. 

 Same blower and coal ; duration of experiment 3 hours 50 minutes — 

 Evaporated 8-62 lbs. water to 1 lb. of coal, and 819-13 Iba. water per 

 hour. 



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