1914] on Surface Combustion 61 



• 925 ; and I am informed that the results of the recent oflBcial 

 tests have confirmed these satisfactory figures. 



As this is the first occasion on which I have been able to refer in 

 public to the successful inauguration of these inventions on a com- 

 mercial scale in Germany, and in anticipation of the publication of 

 the results of the official German trial, I wish, with your kind per- 

 mission, to mention a matter which, although it may appear personal, 

 is nevertheless bound up with the credit of British scientific in- 

 vention. 



This boiler, invented and developed as it was in Leeds, by a 

 group of British chemists, all University trained men, aided by the 

 advice of Mr. Michael Longridge and by the enterprise of my friends 

 of the Skinningrove Iron Co., may truly be claimed as an " all- 

 British" invention, if ever there was one. Nevertheless, it has 

 recently been described in the German technical press as the " Bone 

 Schnabel," or the " Schnabel Bone " boiler, instead of the " Bone- 

 court " boiler, as it should be. It may be necessary at some- future 

 time, to deal more fully with this aspect of the matter, but to-night I 

 will content myself with a protest against any attempt to claim or 

 represent this boiler as, in part, a German invention. 



I have perhaps said enough already about the boiler and its 

 working to convince you that it combines high thermal efficiency and 

 concentration of power, in a unique degree, and perhaps I may be 

 permitted to summarize the other important advantages which may 

 be claimed for it. Firstly, from the constructional point of view, 

 nothing could be simpler or more compact than a cylindrical shell 

 only 4 feet long by 10 feet in diameter, traversed by straight tubes, 

 supported on a casting, and requiring neither elaborate brickwork 

 setting nor expensive chimney flues and stack. Secondly, it has a 

 further advantage over all multitubular boilers in that the front plate 

 can never be heated beyond the temperature of the water, however 

 much the firing may be forced, a circumstance which, coupled with the 

 extremely short length of the tubes, implies an absence of strain and 

 greatly reduces the risk of leaky joints. Thirdly, the high rate of 

 mean evaporation obviates scaling troubles, and the very steep 

 evaporation gradient along each tube causes a considerable natural 

 circulation of water in the boiler, a factor of great importance from 

 the point of view of good and efficient working ; in this connection I 

 may remind you that under normal working conditions we obtain a 

 mean evaporation of 20 lbs. per square foot of heating surface per 

 hour, and can, if need be, force this up to 85 lbs. ; of this total 

 evaporation, 70 per cent occurs over the first third length of the 

 tube, 22 per cent over the second third, and only 8 per cent over the 

 last third. Fourthly, inasmuch as each tube of the boiler is, so to 

 speak, an independent combustion unit, capable of being shut off or 

 lit up without affecting the others, and as it only takes five minutes 

 after lighting up a cold tube to attain its maximum steam output, it is 



