142 



TROPICAL AGRICULTURE 



CHAP. 



How the 

 mills act. 



Megass. 



The impuri- 

 ties of the 

 juice. 



Scum. 



Skimming. 



Charging 

 the boilers. 



Striking 

 from the 

 teache. 

 Granulation 

 of the sugar. 



Draining of 

 the molasses. 



arranged horizontally. In all the mills the canes receive two 

 compressions to force out the juice, and the fibrous material 

 left by the canes after the juice is extracted is called megass, 

 and it is used as fuel for the furnaces under the boiler and 

 clarifiers. 



The cane-juice as expressed by the mill contains in sus- 

 pension various matters such as particles of woody tissue and 

 cellular substances, &c. In order to remove these impu- 

 rities the juice is run into vessels or pans called clarifiers, 

 and a little unslaked lime is added so as to neutralise the 

 vegetable acids. The clarifier is then heated and the impu- 

 rities rise as scum, which is removed and the juice is said to 

 be defecated. The hot juice is now run into the first of a 

 series of cast iron or copper open pans or boilers where it is 

 subjected to great heat. As the juice boils, the scum which 

 rises is skimmed off ; and, in consequence of the evaporation 

 of the water of the juice, the bulk is decreased and the liquor 

 becomes thicker. It is then ladled out into the next boiler, 

 which is smaller than the first one, and more juice is run into 

 the large boiler from the clarifier. As the liquor becomes 

 denser it is transferred from boiler to boiler, which usually 

 decrease in size, until it enters the last and smallest one which 

 is called the teache, and which is usually the fourth boiler. 

 The liquor, which has now become a concentrated syrup, is 

 boiled in the teache until it is in a fit state to granulate into 

 sugar, when it is transferred to flat open wooden coolers, and 

 this is termed striking. The sugar granulates in the coolers, 

 but it is mixed with much uncrystallisable saccharine matter 

 called molasses. After remaining a sufficient time in the 

 cooler the sugar is potted; that is, it is dug out and packed in 

 hogsheads with holes at the bottom for the molasses to 

 drain off. In order to assist the drainage the stalks of 

 the plantain leaves which are long enough to reach the 

 top of the hogshead are put through the holes in the 

 bottom, and they are withdrawn as soon as the molasses 

 are drained off. 



