MANUAL FOR SUGAR GROWERS. 77 



Tins mill is fitted witli two dumb returners, wliicli 

 are hollow, to admit steam or water being forced 

 into tlie megass, so as to combine the advantages of 

 maceration with eftective crushing. 



In Mirlees' four-roller mill the cane is only submit- 

 ted to two crushings, but from the construction of 



Fig. 10.— Diagram of Mirlees' four-roller miU. 



the mill these can be made very effective, Fig. 10. 

 This mill has no dumb returner. There is a dis- 

 position in some quarters to prefer mills of this 

 type in Avhich the rollers work in pairs, each pair 

 only crushing once, instead of three rollers giving 

 three crushings, as in the ordinary three-roller mill. 



Messrs. Thompson & Black's auxiliary rollers, 

 which can be fitted to any ordinary mill, are worth 

 the attention of those whose mills are in fair order, 

 but not powerful enough to give high expression. 



The mill invented by Mr. Skegels, of Demerara, 

 is attracting some attention, and repoiis of its work- 

 ing power are looked forward to with interest. It is 

 a modification of the three-roller mill, and is without 

 a dumb returner,"^'" having besides some new features 

 in its construction. In the De Mornay mill (Fawcett, 



* A revolving bar or small roll is now added to take the place 

 of a dumb returner. 



