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nace is varied according to form and size of boilers, and its 
advantages are : — Effectual consumption of smoke — more 
rapid and increased generation of steam — and at least 25 to 
30 per cent, saving in fuel. If the smoke was not perfectly 
consumed in passing through its own fire, the residue would 
be consumed in the space between the lower and upper grate. 
An interesting discussion ensued, in which Mr. Watson, 
Mr. Eddison, Mr. Ward, Mr. Carter, and others took 
part; during which, Mr. Armytage explained the cost of 
applying the apparatus, and of the patent right, and stated 
that no coals would clinker on the upper grates. In reply to 
the Chairman, he said they had had the apparatus in opera- 
tion ten months : but they were not able to say whether there 
was any liability of the tubes becoming stopped from the 
deposit from the water. There was, however, so rapid a 
circulation through the tubes, that they did not think there 
would be any deposit. In reply to Mr. Swale, he stated 
that the apparatus could only be applied to steam boilers, 
Mr. Eddison said that the apparatus was admitted on all 
hands to be effective, but was there no apprehension of danger 
from the bursting of the tubes ? 
Mr. Armytage replied that the tubes were guaranteed at 
500 lbs. pressure to the square inch, but in order to test this 
question, they had violently broken a tube in the centre with 
a chisel, whilst there was a pressure of 30 lbs. the inch on the 
boiler, and the only result was, that the fire was put out, and 
then all danger ceased. He also added that the apparatus 
had met with the approval of practical men generally, and 
Mr. W. Fairbairn's manager had told him that some boilers 
they were making for Mr. Salt, at Saltaire, and which were 
fitted with this apparatus, would bear a pressure of 100 lbs. 
the square inch. In reply to Mr. Carter, he said there was 
no necessity for high chimneys, but if they did away with the 
chimney, they must have a fan to create a draught. 
