Diffusion versus Double Crushing. 241 



accelerated evaporation takes place without the necessity 

 of making it boil. The rising steam bubbles easily 

 work themselves up in consequence of slow mixing to 

 the surface, until the water percentage of 4 is reached. 

 The boiling is consequently finished in the vacuum pug- 

 mill where a coarse and even grain is obtained. By 

 mixing now with molasses this Massecuite is got ready 

 for curing. The vacuum is then shut and by means of 

 air pressure the movable mass is driven to the centri- 

 fugals. 



Another important item which tends to cheapen sugar- 

 making by means of diffusion is the reduced acre- 

 age which has to be taken into cultivation to reach 

 the same amount of 1st sugar. Having ascertained that 

 with diffusion we require on an average io'39 tons of 

 cane for making one ton of ist sugar, a yearly estimate 

 for making 4,000 tons of ist requires 41,560 tons of cane. 

 To obtain the average yield of an acre with normal seasons 

 and normal labour, taken as 28 tons of cane, we should 

 therefore have to take in cultivation 1,494 acres. 



Considering the exceptional absence of technical 

 training with the generality of the planters, one cannot 

 help being struck by the fa6l that even without it and 

 with machinery and working methods which are con- 

 sidered antiquated in almost all other sugar growing 

 countries, Demerara has been able to keep the posi- 

 tion which it has held up to now as a sugar pro- 

 ducing country. Apart from natural conditions, which 

 are doubtless favourable in this country this is certainly 

 very creditable to the pra6lical common sense and natural 

 intelligence of the Demerara sugar planters ; it has 

 enabled them to carry to its utmost perfe6lion all that 



