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THE NATIONAL GEOGRAPHIC MAGAZINE 



Photograph by American Photograph Company 



CURING WRAPPER LEAVES IN A CUBAN TOBACCO BARN 



The best Havana cigars are made from tobacco that has undergone a curing process lasting 



more than two years (see text, page 32). 



to maintain the boiling process. By this 

 arrangement the juice is boiled to the 

 proper consistency with only one-fourth 

 of the heat otherwise required. 



The next step in the making of sugar 

 is to draw the thick juice into the vacuum 

 pans. Here it comes into contact with 

 hot steam coils and boils at a very low 

 temperature because of the absence of 

 atmospheric pressure. As the boiling 

 proceeds, the sugar crystallizes into small 

 grains. The man in charge of a big 

 vacuum pan is known as the sugar mas- 

 ter. From time to time he adds fresh 

 juice, and its sugar gradually settles on 

 the crystals already formed, which thus 

 are made to grow larger. 



Finally the vacuum pan becomes full 

 of sugar and mother syrup. The sugar 

 and the adhering syrup are then removed 

 to a centrifugal machine that acts some- 

 what on the principle of a cream sepa- 

 rator. Placed inside a perforated basket 

 and whirled around at from 1,000 to 

 1,400 revolutions a minute, all of the 



syrup is forced out through the perfora- 

 tions, while the crystallized sugar re- 

 mains behind. 



This syrup is boiled again, after which 

 it goes to the crystallizer, a huge revolv- 

 ing tank, in which a seed bed of crystals 

 from the vacuum pan has been prepared. 

 There it gradually deposits its sweetness 

 on these crystals, and, when it has given 

 up all that is worth waiting for, the mix- 

 ture goes back to the centrifugal ma- 

 chines, where its adhering syrup is hurled 

 out from this second lot of crystals. The 

 process is repeated again, and by this time 

 all the available sweetness has been ex- 

 tracted, and the remaining liquor is the 

 "blackstrap" molasses of commerce. 



THE PRINCIPLE OP 



The principle of 

 embodied in the fact 

 only a given amount 

 tion. As the water 

 cane juice the latte 

 stage where there is 



SUGAR EXTRACTION 



producing sugar is 

 that water can hold 



of sucrose in solu- 

 is driven out of the 

 r finally reaches a 



not enough left to 



