8.88 TjiAXSACTIOXS OF TUE AMERICAN INSTITUTE. 



tlie fire-pot is suspended witliin a corrugated shell, the air passing 

 between the shell and the fire-pot, combines with the fuel and pro- 

 duces an intense heat without smoke. 



The Chairman remarked that some twenty or thirty patents have 

 been granted on diflferent plans for causing jets or mhiute streams of 

 air to mingle with the hot combustible gases at their point of escape 

 into the remote flues. Few, or none of them, however, appear to 

 have proved successful in practice, or to have been adopted to any 

 considerable extent. 



Mr. G. II. Babcock stated that although smoke burning is a favo- 

 rite idea with engineers, it does not always turn out the most 

 economically when tried. In Milwaukie, Wis., a year ago, he experi- 

 mented with very poor bituminous coal. By an arrangement similar 

 to those mentioned by the Chairman, smoke was eflectually prevented, 

 but its removal, miich to his surprise, while it resulted in the evolu- 

 tion from the fire of a large volume of smoke, gave twenty j^er cent 

 better results from the fuel than before. 



Mr. C. E. Emery said that the inventions mentioned by the Chair, 

 are all founded upon the plan proposed some years ago by Wye 

 Williams. He admitted air in small streamlets through the bridge 

 wall of the furnace. It has since been shown that the useful eftects 

 of the air thus admitted is due chiefly to its mechanical action. The 

 same advantages may be obtained by admitting air through perfora- 

 tions in the lining of the furnace doors. Experiments made in the 

 United States Navy showed an economy of about three per cent from 

 the latter plan, besides securing a reduced temperature in the fire 

 room. 



Mr. J. W. Cole remarked that within the past two or three years, 

 experiments to produce a perfect combustion of anthracite coal were 

 made with a furnace fed from the sides, with a tliin layer of fuel, 

 having an arch over the fire of fire-brick. Tliinking that a saving 

 could be made by the introduction of heated air, another arch was 

 placed over the first, allowing the air to pass between the arches and 

 be distributed into the fire in their sheets at the ends of the brick in 

 the lower arch, the weights being taken of the fuel burned and the 

 water evaporated, it was shown that no saving was made, but a 

 similar furnace erected at the Sligo Iron Works, also at Pittsburg 

 Water Works, in Pennsylvania, showed this device to be well adapted 

 to a quite thorough combustion of the smoke. These furnaces seemed 

 to prove that the most economical fires M'ere made by giving not 



