THE PASTEURIZATION OF MILK 



the boiling point. One feature of this machine 

 is unique. The machine is so constructed that, 

 when the final rinse water falls below a definite 

 temperature,, of say 180, it refuses to operate, 

 since the bottles will not be lifted from the rinse 

 tank, but will remain submerged. The machine 

 thus becomes its own thermostat. This effect is pro- 

 duced in the following manner: The platform 

 upon which the cases are placed, and by means of 

 which they are lowered into and lifted from the 

 rinsing tank, is so counterbalanced that when the 

 bottles are full of water the weight is too great 

 for the case to be lifted. If the water which is 

 forced into the bottles is hot enough so that as re- 

 leased from pressure it is converted into steam, 

 then the water is forced out of the bottles, and they 

 have sufficient buoyancy to enable the counter- 

 weight to lift the entire case out of the tank. 



The older method used in washing bottles, even 

 when large quantities were handled, was to pro- 

 vide means for soaking the dirty bottles, then to 

 wash them by hand on revolving brushes, and 

 finally to sterilize them in separate rooms, or in 

 tanks into which live steam was discharged for a 

 considerable time. This method is still in use to 

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