78 THE INVISIBLE WORLD 



crobe. A beer yeast is generally used to inoculate 

 the mixture. It will secure quicker and more vig- 

 orous fermentation. When the fermentation ceases, 

 the work of the microbe is done; the sugar of the 

 materials is all converted into alcohol and car- 

 bon dioxide. We now want only the alcohol. 

 The wort, after it is strained, may contain ten 

 per cent; the rest, ninety per cent, is water. 



The problem now is, to separate the water, or 

 at least a large portion of it, from the alcohol. 

 This is done by distillation. In Fig. 54 is shown 

 just enough of the apparatus to explain the princi- 

 ple. It consists of a retort, a, set in furnace, b, 

 the condenser, c, the receiver, d, and the pipe or 

 worm, e, reaching from the retort over, and down 

 into, and through, the condenser to the receiver. 



Fill the condenser with cold water and ice. Fill 

 the retort, one hundred gallons, with the 

 liquor to be distilled. Ten gallons of it are al- 

 cohol; ninety, water. Under the retort kindle the 

 fire in the furnace. Heat the liquor to 175 de- 

 grees; no more. At this temperature the alcohol 

 boils and passes into steam, but the water does not. 

 To boil and convert the water into steam requires 

 a temperature of 212 degrees. Keep the tempera- 

 ture in the retort, therefore, steadily at 175 de- 

 grees. The alcohol passes into vapor. The vapor 

 rises into the pipe. The water remains behind. 

 This is what you want the separation of the 

 alcohol from the water. This is distillation. In 

 due time, all the alcohol in the retort ten gallons 



