QUANTITATIVE METHODS OE ANALYSIS 



153 



it to tlie Gooch by shaking it up in the water and pouring 

 it quickly into the crucible while under suction. The 

 excess of fine asbestos should be poured off before adding 

 to crucible. 



6. Dry the Gooch with its contents in the oven, and 

 finally heat to dull redness for fifteen minutes, during which 

 the red cuprous oxid is converted into the black cupric 

 oxid. Considerable care must be taken to avoid cracking 

 the crucible, the heat being increased cautiously, and the 

 operation conducted preferably in a muffle furnace. 



7. After oxidation as above, the crucible is transferred to 

 a desiccator, cooled, and quickly weighed. 



8. From the milligrams of cupric oxid calculate the 

 milligrams of dextrose according to the following table: 



Leech, Food Inspection and Analysis, New York, p. 595, 1913. 



Def fen's Table for Dextrose, Maltose ^ and Lactone 



Cupric oxid. 



Dextrose. 



Maltose. 

 Mgm. 



Lactose. 



Cupric oxid. 



Dextrose. 



Maltose. 



Lactose. 



Mgm. 



Mgm. 



Mgm. 



Mgm. 



Mgm. 



Mgm 



Mgm. 



30 



13.2 



21.7 



18.8 



180 



80.4 



131.8 



114-6 



40 



17.6 



29.0 



25.2 



190 



84.9 



139.X 



121.0 



SO 



22.1 



36.2 



3I-S 



200 



80.5 



146.6 



i?7.5 



60 



26.5 



43.S 



37-8 



210 



94.0 



154.1 



134.1 



70 



30-9 



S0.8 



44.1 



220 



98.6 



161.S 



140.6 



80 



354 



58.1 



S0.5 



230 



103. 1 



169.I 



147.0 



90 



39-9 



65.5 



56.8 



240 



107.7 



176.6 



153.5 



100 



44.4 



72.8 



63.2 



250 



II2.3 



184.I 



160,0 



no 



48.9 



80.1 



69.5 



260 



116,9 



191. 6 



166.5 



120 



S3-S 



87.4 



75-9 



270 



121.4 



199.2 



173.0 



130 



S7.8 



94.8 



82.4 



280 



126.1 



206.8 



179.6 



140 



62.2 



102. 1 



88.7 



290 



130.7 



214.3 



186.2 



ISO 



66,S> 



109.5 



95.2 



300 



135.3 



221.9 



192.8 



160 



71.3 



I16.9 



101.7 



310 



139.9 



229.6 



199.3 



170 



75.8 



124.4 



108.2 



320 



144.5 



237.2 



205.9 



