190 VINEGAR, CIDER, AND FRUIT-WINES. 



quantity of the ferment, which rapidly augments on coming in 

 contact with a fluid favorable for its development. 



The vats are charged by allowing the fluid to be converted into 

 vinegar to flow in until it begins to run out through g. The 

 setting with ferment is then effected by carefully emptying the 

 contents of one of the plates upon the surface of the fluid, so that 

 the greater portion remains floating upon it. Finally the lid is 

 placed upon the vat and the latter left to itself. 



The ferment soon covers the entire surface of the fluid in the 

 vat, and the commencement of the process of oxidation is in a 

 short time recognized by the rise of the thermometer dipping into 

 the fluid. As long as the quantity of alcohol in the fluid is com- 

 paratively large the process of the formation of acetic acid and 

 the augmentation of the ferment take place very rapidly and the 

 thermometer rises constantly ; but with an increase in the quan- 

 tity of acetic acid these processes become slower, which is indi- 

 cated by a fall in the temperature of the fluid. The energy of 

 the process must, however, not be allowed to sink below a certain 

 limit, care being had to keep it up by raising the temperature of 

 the workroom, but not higher than is absolutely necessary for the 

 correct working, as otherwise there would be a loss of acetic acid 

 or alcohol by evaporation. 



The most convenient and business-like manner of operating a 

 factory arranged as above described is to simultaneously charge 

 all the vats with alcoholic liquid, it being then entirely in one's 

 power to regulate the heating of the workroom according to the 

 indications of the thermometer dipping into the fluid. If, for 

 instance, the operation commences at 77 F., the thermometer 

 will soon be observed to rise even if the temperature of the work- 

 room remains unchanged. By the oxidation of the alcohol suffi- 

 cient heat is liberated to increase the temperature of the fluid to 

 above 95 F. ; it is, however, advisable not to allow it to rise 

 above 86 or 90 F., as otherwise the losses by evaporation are 

 too great. Hence, if the fluid reaches this limit of temperature 

 the heating of the workroom is so regulated as to prevent a fur- 

 ther rise of the thermometer, and a constant temperature is 

 maintained for several days until it commences to fall almost 

 simultaneously in all the vats. This fall in the temperature, as 



