EVAPORATION OF FRUIT. 409 



tray is raised five inches by means of the endless chain ; the second 

 tray is then placed in position, but so that the above-mentioned 

 intermediate space is at the back wall. At regular intervals the 

 trays, when placed in position, are raised by the endless chain 

 and the fresh trays pushed in, so that they touch alternately the 

 front and back wall, the current of hot air being thus forced 

 to ascend in a zigzag. When the tower is filled with trays it 

 contains taking apples as an example from 1200 to 3000 Ibs. 

 of fruit, every 50 Ibs. of each yield from 40 to 45 Ibs. of water, 

 which ascends as vapor, which by surrounding the fruit with a 

 moist mantle prevents its burning and keeps the pores open. 

 When the tray first placed in position arrives at the discharge- 

 door it has been in the tower for about five hours, and its contents 

 have been converted into evaporated fruit which will keep for 

 many years. Thus fruit can be gathered, evaporated, and sold 

 all in one day. 



By considering the construction of the tower it will be seen 

 that the fruit during its ascent remains in a uniform moisture and 

 heat, so that up to the moment it is taken from the apparatus, its 

 content of water can escape through the opened pores and, on the 

 other hand, the heat can act to its very centre. A uniform, per- 

 fect product can be obtained only by these means. When the 

 fruit arrives at the discharge-door it is cool and as soft as fresh 

 fruit. 



We will here call attention to a sun-drying apparatus, shown 

 in Fig. 77, which may be recommended to those who do not 

 wish to employ artificial heat, and are forced to give the prefer- 

 ence to as cheap an apparatus as possible. The apparatus is con- 

 structed of boards and window-glass. The board walls, which 

 are somewhat inclined outwardly, project above the panes of 

 glass and serve, as is readily seen, for catching the rays of the 

 sun. .They are lined inside with tin, thus becoming reflectors. 

 The side door serves as an entrance to the apparatus when the 

 panes of glass are to be cleansed or repairs are to be made in the 

 interior. The trays containing the fruit are pushed in from the 

 back, the entrance of each tray being covered by a wooden flap. 

 According to the size of the apparatus two or three rows, each 

 consisting of twelve trays, are placed alongside each other. Above 



