SACCHARINE PRODUCTS. 



65 



matter. Use a weighing bottle provided with a cork through which a pipette 

 passes if this weighing can not be made with extreme rapidity. Place the dish 

 In a water oven and dry to constant weight at the temperature of boiling water, 

 making trial weighings at intervals of two hours. In case of materials con- 

 taining much levulose or other readily decomposable substances, conduct the 

 drying in vacuo at about 70 C. 



(3; FOB DRYING MOLASSES WITH QUARTZ SAND. PROVISIONAL. 



In a flat-bottom dish place 6 or 7 grams of pure quartz sand and a short 

 stirring rod. Dry thoroughly, cool in a desiccator, and weigh. Then add 3 or 

 4 grams of the molasses, mix with the sand, and dry at the temperature of boil- 

 ing water for from eight to ten hours. Stir at intervals of an hour, then cool 

 in a desiccator, and weigh. Stir, heat again in the water oven for an hour, cool, 

 and weigh. Repeat heating and weighing until loss of water in one hour is not 

 greater than 3 mg. 



Before using, digest the pure quartz sand with strong hydrochloric acid, wash, 

 dry, ignite, and keep in a stoppered bottle. 



(b) ABEOMETBIC METHODS.** OFFICIAL. 



(1) SPECIFIC GRAVITY, WATEB, AND TOTAL SOLIDS BY MEANS OF A SPINDLE. 



The density of juices, sirups, etc., is most conveniently determined by meana 

 of the Baume or Brix hydrometer, preferably the latter, as the graduation of 

 the scale gives close approximations to the percentages of total solids. The 

 Brix spindle should be graduated to tenths. The range of degrees recorded by 

 each individual spindle should be as limited as possible. The solution should be 

 as nearly as practicable of the same temperature as the air at the time of 

 reading, and if the variation from the temperature of the graduation of the 

 spindle amounts to more than 1, a compensation must be applied according to 

 the table of corrections for temperature, page 67. Before taking the density of 

 a juice it should be allowed to stand in the cylinder until all air bubbles have 

 escaped. 



In case the sample is too dense to determine the density directly, dilute a 

 weighed portion with a weighed quantity of water, or dissolve a weighed portion 

 and dilute to a known volume with water. In the first instance the per cent 

 of total solids is calculated by the following formula : 



WS 



Per cent of solids in the undiluted material = - 



\v 



S=per cent of solids in the diluted material. 

 W=weight of the diluted material. 

 w=weight of the sample taken for dilution. 



When the dilution is made to a definite volume, the following formula is to 

 be used : 



VDS 



Per cent of solids in the undiluted material = 



W 



V= volume of the diluted solution. 

 D=specific gravity of the diluted solution. 

 S^per cent of solids in the diluted solution. 

 W=weight of the sample taken for dilution. 



This method does not apply to low-grade sugar products since materials high in salts 

 give excessive percentages. 



