42 SUGAR 



The apparatus for doing so is constructed and worked 

 in the following way. A number of large vertical 

 cylindrical vessels are ranged either in rows or in a 

 circle. They are furnished with a well secured man- 

 hole at the top and bottom, and with pipes which 

 convey hot water to each vessel, and others which convey 

 the liquid from each vessel to its next door neighbour, 

 passing on their way through a heater which keeps the 

 liquid up to a certain temperature. The pipes are 

 arranged so that the liquid can be passed from one 

 vessel to another either at the top or the bottom, or 

 can be drawn off when the process of diffusion is com- 

 pleted. On the floor which commands the top of this 

 battery of vessels are the valves by which the man in 

 charge is able to conduct the operations. On an upper 

 floor is the machine which cuts the roots into slices, 

 all of the same size and shape, so that they can lie in 

 the vessels without getting jammed together, but 

 leaving room for the water to flow freely round them. 

 If the battery is arranged in a circle the slices from above 

 can be directed by a revolving shoot into any one of 

 the vessels. On the upper floor is also the hot-water 

 tank, situated sufficiently high to give the necessary 

 pressure for the circulation of the liquid through the 

 vessels of the diffusion battery. 



Let us suppose that all the vessels (8, 12, 14 or 16, 

 as the case may be) are filled with slices, and the openings 

 at the top through which the slices have been shot 

 securely closed. Hot water from above is then turned 

 on to the first vessel until it is full. Diffusion of the 

 sugar takes place, and the density inside and outside 

 the cells begins to approach to uniformity. Before the 

 diffusion seriously slackens its pace the water now 

 a weak solution of sugar is passed on to the second 

 vessel, after traversing the intermediate heater, and 



