68 ANNUAL OF SCIENTIFIC DISCOVEKY. 



IMPROVEMENT IN FURNACES. 



Dr. B. H. Washburn of St. Louis, has invented a method of feeding air to 

 boilers, on the so-called " tornado principle." The arrangement is as follows: 

 Two connecting cones or runnels are inserted in the doors of the furnace, 

 which insures a steady draught, and gives the air the form of a whirlwind. 

 The ash-pit is inclined at a good angle, reaching the bottom of the boiler from 

 the door in the space of a few feet, and thus every particle of heat is saved 

 and applied to the surface with the greatest intensity. 



Smoke-consuming Furnace for Bituminous Coal. Messrs. Haughgrove and 

 "Wheatly, London, have obtained a patent for a new furnace to consume the 

 smoke of bituminous coal. The furnace is fitted with two sets of grate bars 

 slightly inclining upward toward the back end. Between the front and back 

 set of bars a hollow perforated movable bridge or partition is fitted, and con- 

 nected with a lever, by which the fireman can move it up or down. When 

 this bridge is depressed, access may be readily had to the back bars from the 

 front ones. A bright glowing fire is kept in the back bars or grate by push- 

 ing back the incandescent fuel from the front one. After the back grate is 

 supplied with glowing coals, the central bridge is raised, and all communi- 

 cation between the two fires is cut off, except through holes or perforations in 

 the bridge. When fresh fuel is thrown on the front grate, a large quantity 

 of unconsumed gases are immediately evolved, which, in passing through the 

 perforations in the movable central bridge, are there mingled with a current 

 of warm air coming from below the furnace through the hollow part of the 

 bridge, and then pass in streams over the back fire, ignite, and are consumed 

 i'n other words, converted entirely into carbonic acid gas, with a great de- 

 velopment of heat. A door is placed behind the farthest set of bars for the 

 purpose of cleaning out the back furnace. 



Macferran's Self-retaining Grate Bars. These patent bars have mortices 

 on one side and tennons on the other, at the part where the bars touch each 

 other, so that when a set are placed side by side with the tennons of one fit- 

 ting in the mortices of the next, it is impossible for one bar to rise above an- 

 other. This preserves a uniform level at the top, and prevents them from 

 warping. 



Solo's Doivn-draught Smokeless Furnace. In this furnace, devised by Mr. 

 R. H. Bow of Scotland, the draught is reversed that is, the flame, air, etc., 

 proceed downward through and from the fire ; and it is therefore, proposed to 

 call it the "Down-draught Furnace." The principle of its action is very sim- 

 ple. The smoke, liberated from the superincumbent coal, is, by means of the 

 suction of the chimney, carried, along with a due admixture of air, down 

 through the brightly burning fuel which forms the lower stratum of the fire, 

 and thus becomes intensely heated and completely burned. Contrary to what 

 might have been expected, the combustion is very rapid ; in some experi- 

 ments made with a grate of of a square foot in area, the combustion was at 

 the rate of 301bs. of coal per square foot of grate per hour; the height of the 

 chimney being nearly 35 feet. This result is probably due to the self-clear- 



