ARRANGEMENT OF A VINEGAR FACTORY. 



71 



*. 19. 



1L-55 



the jacket, is opened. The furnace being heated the air in the 

 room is sucked in the direction of the arrow through the flue L, 

 and passing between the jacket and the furnace, ascends strongly 

 heated through and penetrates through the openings in the 

 channel ; air is again sucked through L, and so on. 



If, however, the air in the workroom is to be entirely renewed, 

 the air-flue L is closed and a register (not shown in the illustra- 

 tion) in the lower part of the jacket opened. 

 In this case the air in the cellar is sucked in, 

 heated and distributed through the channels 

 C and C v By partially opening this register 

 and that in L a portion of the air can be re- 

 newed at will. 



In order to be able to form a correct idea 

 of the state of the temperature prevailing in 

 the room, it is advisable to have several or- 

 dinary thermometers and also a maximum 

 and minimum thermometer. If the latter 

 show r s no greater variation than from 4 to 

 5, the process of heating may be considered 

 as satisfactory. 



A very suitable apparatus for controlling 

 the temperature in a vinegar factory is au 

 electrical thermometer, which is so arranged 

 that a bell rings in case the temperature rises 

 above or falls below a certain degree. By 

 placing two such thermometers in the room, 

 the bell of the one indicates the rise of the 

 temperature above the limit, and that of the 

 other that it has fallen below it. 



Fig. 19 illustrates the principle of a maxi- 

 mum electrical thermometer, i. e.> one which 

 rings a bell when the temperature of the room 

 exceeds a certain limit. Into the bulb of an 



Maximum Electrical 



ordinary mercury thermometer is melted a Thermometer, 

 platinum wire ; another platinum wire is in- 

 serted in the tube up to the mark indicating the temperature not 

 to be exceeded, for instance, 35 C. The ends of the platinum 



-35 



=-30 



=-20 



=-15 



