SUGAR REFINING 85 



that the million do not demand so much low-priced 

 yellow sugar as they used to do. The consequence is 

 that the British refiner finds it well to use a higher 

 class of raw sugar. For some forty years, up to the 

 outbreak of war, he had an abundant supply of good, 

 strong, and fairly clean raw beetroot sugar, and that is 

 what he has lived upon. So much so in fact, that at 

 one time there were only one or two refineries in the 

 Kingdom who could guarantee that their sugar was 

 " Pure Cane." As far as this country was concerned, 

 beetroot had established pretty nearly a monopoly. 



The reader may perhaps wish to know how the 

 Scottish refiners managed to boil their yellow sugars 

 at a low temperature. The vacuum pan has already 

 been described, but the method of condensing the vapour 

 rising from the boiling sugar has not been given in detail. 

 It used to be done by interposing a jet of cold water 

 in the course of the wide pipe which goes from the neck 

 of the pan to the air pump. This condensed the vapour 

 and thus helped to increase the vacuum. The air 

 pump took away the water of this condenser as well 

 as the condensed vapour. This pan would boil at 

 about 160 F. But to boil at 140 F required a much 

 better vacuum. This meant that the pan and its con- 

 nections must be very air-tight that is, very well 

 made that the air pump must be very powerful, and 

 that the condensing power must be greatly increased. 

 This was done by making a condenser with a vertical 

 pipe the length of a column of water held up in a vacuum 

 tube by the pressure of the atmosphere. Under these 

 conditions a larger condenser could receive a plentiful 

 flow of cold water, because the water would flow away 

 down the pipe instead of through the air pump. The 

 water was scattered about the inside of the condenser 

 in such a way as to present the largest possible surface 



