272 BEETROOT SUGAR IN FRANCE. 



the pulp is enclosed in bags, and the latter subjected to 

 pressure ; at least this is the process commonly adopted. In 

 1867, however, being commissioned by a city firm to visit a 

 beetroot-sugar factory in Cambrai, wherein, as had been re- 

 presented, some new and elaborate appliances of pressure 

 and chemical treatment were adopted, I was gratified beyond 

 expectation. I saw a wholly novel mode of applying hydro- 

 static pressure, to describe which would necessitate mechanical 

 details foreign to the scope and intent of this notice. If by 

 chance, however, some exceptionally practical reader should 

 desire to be made acquainted with mechanical particulars, he 

 may do so by reference to two special journals, in each of 

 which at the time I wrote an article ; they are the Engineer 

 and the Grocer. 



We have now arrived at the beetroot juice itself colour- 

 less and liquid enough to view, but offensive to smell, and 

 loaded with an amount of nitrogenous and other foreign 

 matters, the bulk of which must be seen to be appreciated. 

 By one means or another these impurities must be separated, 

 the greater part of them at least ; otherwise no evaporation 

 would crystallise the sugar out. This separation is now in- 

 variably effected by heating with quick-lime, which has the 

 double effect of neutralising acidity, and so far decomposing 

 the nitrogenous impurities that a large bulk of them separates 

 as scum, separable by skimming and filtration. As regards 

 the mode of filtration adopted, it is twofold partly through 

 cotton bags of peculiar make and texture, partly through 

 bone-black which has been exhausted as to its bleaching or 

 chemical effects, but which can still act mechanically as a 

 very efficient filter to effect separation of albuminous flocculi 

 which may have come through the weft and woof of a cotton 

 bag. The fact may here be indicated, that although beetroot 

 juice is nearly colourless when first extracted, the process of 

 heating with lime imparts colour, which deepens with every 

 subsequent evaporative stage. 



