105 



SUGAR-BOILING TEST, HACIENDA CARMENCITA, PONTEVEDRA (FEBRUARY 9, 1909). 



The equipment consists of two sets of "cauas," six in a series, worked in- 

 dependently, and two large clarifying tanks, which in reality serve more as storage 

 tanks, since very little clarification takes place in them, and the raw juice is 

 often run directly from the mill to the "cauas" without entering the tanks at all. 

 Ordinarily, the juice is pumped from the mill bed to these tanks, where it stays 

 from fifteen to thirty minutes, and is heated by exhaust steam to about 60°. some 

 of the lighter impurities in the meantime rising to the surface and being skimmed 

 off. The warmed juice flows by gravity from the tanks into "caua" No. 6, 

 and when this is full overflows into No. 5, where it remains some fifteen minutes 

 before liming. Juice begins to boil in Nos. 3 and 4, which soon boil over, and the 

 scums are swept back into No. 5, there to be skimmed off and thrown into a scum 

 tank. Aside from these details, the procedure is the same as that previously 

 described. As it is only a semicontinuous process, juice being periodically ladled 

 from one kettle to another as each "cocida" is taken out and "caua" No. 1 

 emptied, an attempt was made to follow the course of one lot of juice, taking 

 samples each time it was transferred from one "caua" to the other throughout 

 the series. It was found impossible to do this absolutely, since the juice in each 

 "caua" is always more or less mixed with that boiling back from the one in front 

 or ladled in from the one behind it. As canes from the same field were being 

 ground, the mill juice was fairly constant, so that but little variation can be 

 attributed to this factor. 



A barely perceptible inversion apparently took place as long as the raw juice was 

 being heated without liming, as shown by the increase of reducing sugars over 

 sucrose. The excess of lime in the fourth sample evidently had a slightly destruc- 

 tive action on the invert sugars formed, since their ratio to sucrose drops a trifle. 

 From here on it increases slowly, but the final ratio in the sugar produced is only 

 1.7 per cent higher than that of the original juice, so that very little loss can be 

 traced directly to inversion, as sho-wn by the reducing sugar ratio. The pro- 

 babilities are that very much more inversion has actually taken place than is here 

 indicated, but that, owing to the well-known destructive action of lime salts on 

 glucose and fructose at high temperatures, these products have been immediately 

 decomposed into carbonic, formic, and acetic acids, etc., and hence can not be 

 detected by analysis. The apparent purity of the juice falls slowly, down to the 



