408 VINEGAR, CIDER, AND FRUIT-WINES. 



The draught-pipe d connects the exit of the drying-tower with 

 the fire-box of the furnace. The importance of this ventilation is 

 sufficiently shown by the statement that for combustion 25,000 

 cubic feet of air per hour are required, which are introduced from 

 the neighborhood of the opening of the tower through the pipe d 

 into the fire-box. The removal of such a considerable quantity 

 of air produces a vacuum in the upper portion of the tower, and 

 consequently a very quick current of air over the trays of fruit 

 in the tower an absolute requirement for attaining great perfec- 

 tion in the art of drying fruit by evaporation. Besides, a saving 

 of fuel is effected by the introduction of air already heated into 

 the fire-box. The smoke-pipe is surrounded by a wooden 

 jacket leaving a small intermediate space in which the heat radi- 

 ating from the pipe collects, and is forced to enter the tower be- 

 low the discharge-door. This also accelerates the current of air 

 in the tower and prevents the condensation of the moisture, so 

 that the fruit completely dries off in a short time. The branch- 

 pipe / connects the opening of the tower with the smoke-pipe, 

 which by its power of absorption also increases the current of air. 

 The <Jraught-pipe c is provided, as will be readily seen, for the 

 purpose of uniformly distributing the heat in the tower. 



The bulb of the thermometer, with which the apparatus is pro- 

 vided, is placed in the interior of the tower and the scale on the 

 outside, so that the temperature can be read off without opening 

 a door, whereby cold air would enter, which must be avoided. 

 The air-furnace is constructed of brick, and the tower, as well as 

 the draught-pipes d and c and the jacket of the smoke-pipe 0, of 

 double boards. 



The hurdles or trays for the fruit consist of wooden frames 

 with galvanized iron wire bottoms. They hold from 20 to 60 

 Ibs. of fruit each, and when charged are pushed through the door 

 over the air-furnace into the tower, where they rest upon pins of 

 an endless chain set in motion by a wheel, as seen in the illustra- 

 tion. The trays sit close to the walls on two sides of the tower, 

 while in the other direction there is an interspace of two inches. 

 The first tray is pushed tight against the back wall, the men- 

 tioned interspace thus remaining in front of the door. 



After six to ten minutes, according to the variety of fruit, the 



