4G ANNUAL OF SCIENTIFIC DISCOVERY. 



pose of compelling all the owners of factories to use furnaces for the pre- 

 vention of this smoke evil. In 18-3-3 a prize of .300 ($-2-500) was offered by 

 the Colliers' Association of Xewcastle, and was contended for in December 

 18-37, for the best method of burning bituminous coals in furnaces of mul- 

 titubular boilers without smoke. On that occasion, the prize was awarded 

 to C. W. Williams, of Liverpool, he having produced the best furnace and 

 system of feeding the fuel to it. The report of the judges on the trials has 

 but recently been published, and from it we obtain information which is of 

 the utmost importance to consumers of bituminous coal. 



It has been demonstrated, to the satisfaction of the most able engineers 

 on the other side of the Atlantic, that bituminous coals can be burned in 

 furnaces without producing smoke; and this by a very simple construction 

 and arrangement of the furnace doors, and the method of feeding the coal. 

 The whole system consists in having the furnace doors made with double 

 plates, the inside one situated a few inches apart from the outside, so as to 

 form, a small chamber between them. The front and back plates are per- 

 forated with holes, or slits, and the air is heated as it passes through into the 

 fire. The small holes deliver the air to the fuel in minute currents, and the 

 fresh coals are fed to the fire by being laid right behind the door, the red 

 coals being pushed forward every time the fresh are fed in. This arrange- 

 ment of furnace doors, and the method of feeding, entirely prevents smoke, 

 upon well-known principles. When fresh bituminous coal is thrown upon a 

 red-hot fire, the more volatile part passes off as smoke; were this supplied 

 with fresh air, and made to pass over a red-hot fire, it would ignite and be 

 consumed. The air which passes through the holes in the furnace door, 

 mixes with the volatile products of the fresh coal, and these are ignited as 

 they flow over the fire on their way to the flue tubes. Of course, air is also 

 admitted in the usual manner under the furnace bars, which should be half 

 an inch thick at the top, and very thin at the bottom, and an air space of 

 three-eighths of an inch left between them ; such furnaces are made a little 

 longer in front than the common kind; no other alteration is necessary, 

 excepting perforating the door. 



With furnaces so constructed, one foot of grate surface has evaporated 

 four cubic feet of water per hour, from GO 3 Fahrenheit, which is double the 

 amount usually obtained; and the economy of fuel has been over twenty- 

 five per cent. With such furnaces, 11.30 Ibs. of water have been evapor- 

 ated with one pound of coal, and owing to the fresh coal being always 

 placed close to the door, the heat in the fire-room is but low, while the 

 doors are kept cool, and thus they last much longer. In employing bitumin- 

 ous coal in a multitubular boiler, the whole fuel should be perfectly burned 

 in the furnace, the flame running the whole length of the fire; as the in- 

 flamed gases, if just ignited near the mouth of the tubes, are very liable to 

 be extinguished when they enter them, and thus great loss of heat is sus- 

 tained. Furnaces in which anthracite coal is burned, do not require such 

 arrangements, because no volatile combustible matter is given off from this 

 fuel. Scientific American. 



GRIFFIN'S IMPROVED GAS FURNACE. 



An improved furnace, for laboratory and manufacturing purposes has 

 been patented during the past year, by Mr. Griflin, the well-known chemist, 

 of London; by which, standing on a table, or any other convenient place, an 



