THE ASSAY OF SUGAR HOUSE PRODUCTS. 



in excess the juice remains red, becoming finally colourless when the lime is 

 neutralized. Each ten divisions in the tube correspond to ! grm. lime per 

 1000 c.c. For juice of the second saturation a weaker acid only one-fifth 

 the strength of the above is used. 



The determination of the total lime in the juice is performed by the 

 usual methods; 100 c.c. juice are heated to boiling, ammonia added in 

 excess and filtered if necessary ; the lime is precipitated by ammonium 

 oxalate from the hot solution, boiled for two hours, filtered, washed, dried, 

 and weighed as carbonate or sulphate. 



A 



The alkalinity of a juice is in part due to caustic soda and 

 potash set free by the action of lime on the salts of the former 

 present in the juice ; when it is wished to determine the alkalinity 

 due to lime and to soda and potash, Pellet's method may be used, 

 1 . Determine the total alkalinity by titration with sulphuric acid r 

 using litmus as an indicator and making the titration at the boiling 

 point. 2. To a volume of the juice add an equal bulk of alcohol 

 which will precipitate the lime as an insoluble saccharate ; filter, 

 and in an integral part of the filtrate determine the alkalinity ; 

 the latter is due to free caustic potash and soda but is expressed 

 as lime for purposes of convenience ; by determining the total 

 lime, the combined lime can be likewise obtained. 



Analysis of Massecuites and Molasses. The 



FIG. 264. sugar, glucose, ash, alkalinity, gums, moisture, &c., are determined 

 by the general methods already given. 



Density. The density of a massecuite has a two-fold meaning : firstly, 

 the apparent density of the material as it actually exists, a figure required to 

 calculate the weight of the factory product from its cubage, and secondly the 

 true density required in the control of the boiling. 



The method used by the writer is as below : 

 A large wide-mouthed vessel of the slope shown in Fig. 265 is 

 constructed of copper or brass, or even a wide-mouthed bottle may 

 be employed, if the mouth of the vessel is formed sloping inwards 

 and a stopper is ground accurately to fit this mouth ; through the 

 centre of the stopper is bored a hole about in. in diameter. 

 Massecuite from the pan is allowed to flow into the vessel until 

 about seven-eighths full ; the vessel is then allowed to cool until 

 it has reached the temperature at which the factory measurements 

 of massecuite are taken, and the weight of massecuite determined. Water is 

 then carefully poured over the surface of the massecuite till the vessel is full, 

 the stopper inserted, when the excess of water escapes through the aperture 

 and is wiped off. The method of calculation is shown below : 



FIG. 265 



483 



