JOHlSr A. WILLIAMS. 253 



direct, but converting it into carbonic oxide by burning 

 coal with a limited supply of air. The gas so produced 

 passes through retorts into the regenerative chambers of 

 the melting furnace. At first this regenerative gas 

 principle was applied to the pot furnace then in use, but 

 soon furnaces of far different construction were employ- 

 ed. The general plan of construction was in the form of 

 a basin or tank, covered with a low arch. The length is 

 usually about 30 ft., width 16 ft. and depth 3 ft. The tank is 

 divided into one or more compartments either by float- 

 ing or stationary bridges. At one end of the furnace is 

 an opening for feeding in the batch, and at the opposite 

 end are a number of openings called working holes, 

 through which the molten glass is extracted. The flues 

 through which the air and gas enter the furnace, are 

 located at the sides. Underneath this furnace are 

 situated the regenerative chambers, which are built up 

 with brick in the form of checker work, so arranged that 

 there is suflBcient space between the brick for easy access 

 of the gas and air. 



These chambers are arranged in sets on each side of 

 the furnace, one part of each set being used for the sup- 

 ply of air, the other for the supply of gas. By means of 

 valves it is possible to connect either set of chambers 

 either to the gas retorts, or to the flue leading to the 

 chimney stack. When the gas from the producer en- 

 ters one of the regenerative chambers it is forced 

 through by the pressure of gas behind it, and at the en- 

 trance to the furnace it comes in contact with a volume 

 of air which has been forced through the corresponding 

 chamber of this set. Combustion then takes place, and 

 the flame spreads across the furnace over the batch, and 

 escapes through corresponding flues on the opposite 

 side of the furnace, which lead to the second set of re- 

 generative chambers, at this time in connection with the 

 chimney flue. The escaping gases impart to the brick 



209 



