160 AGRICULTURE 



Yields of sugar cane. In Hawaii, where the canes are 

 allowed to grow much longer than in the United States 

 before being cut, the yield has been as high as 100 tons 

 of cane per acre. Irrigation is largely responsible for the 

 large yields in those islands. This greatly increases the 

 yield on well-drained land in the Southern states. A 

 good average yield for an entire sugar estate in Louisi- 

 ana is 20 to 30 tons per acre ; for sandy pine lands, 1 5 to 

 20 tons. A good yield of syrup is from 300 to 600 gal- 

 lons per acre. Large steam mills press the juice from 

 the cane much more completely than do the small mills 

 worked by horse power. The large plantations are equipped 

 with very large and expensive mills. 



Making syrup. The usual outfit for a small cane mill 

 and evaporator is not expensive. The evaporator is a 

 large shallow pan with a copper bottom. In this the juice 

 is boiled until thick enough for syrup. It is usually 

 placed just above a furnace. Sometimes boiling is done 

 by steam carried through coils of pipes laid in the bottom 

 of the usual evaporator pan. 



Even experienced syrup-makers can make a more uni- 

 form article by placing in a bottle of the hot syrup a 

 simple instrument (Baum hydrSm'eter) for showing how 

 thick it is. When this sinks to a point between the marks 

 34 and 35 degrees on the instrument, the boiling is 

 stopped. 



To prevent a part of the syrup turning to sugar, it may 

 be put in cans or jugs while still very hot and tightly 

 sealed to exclude the air. The heat kills the germs and 

 thus keeps the syrup from fermenting. 



