IX] SACCHARINE PRODUCTS 137 



53 REDUCING SUGARS AS INVERT SUGAR.-TENTATIVE. 



(a) Before inversion. — Proceed as directed under VIII, 25, using an aliquot of 

 the solution used for direct polarization, 55 (a), and only neutral lead acetate for 

 clarification. 



(b) After inversion. — Proceed as directed under VIII, 25, using an aliquot of 

 the solution used for the invert polarization, 55 (b), and only neutral lead acetate 

 for clarification. 



SUCROSE. 



57 Bij Polarization. — Tentative. 

 Proceed as directed under VIII, 14 or 16. 



58 By Reducing Sugars Before and After Inversion. — Tentative. 

 Proceed as directed under VIII, 18. 



59 TOTAL ASH.— TENTATIVE. 

 Proceed as directed under 13. 



80 SOLUBLE AND INSOLUBLE ASH.— TENTATIVE. 



Proceed as directed under 17. 



61 ALKALINITY OF THE SOLUBLE ASH.— TENTATIVE. 



Proceed as directed under 18. 



62 ALKALINITY OF THE INSOLUBLE ASH.— TENTATIVE. 



Proceed as directed under 19. 



LEAD NUMBER (WINTON).— TENTATIVE. 



63 REAGENTS. 



Standard basic lead acetate solution. — Boil 430 grams of normal lead acetate and 

 130 grams of litharge, for 30 minutes, or boil 560 grams of Home's dry basic lead 

 acetate with 1 liter of water, cool, allow to settle and dilute the supernatant liquid 

 to 1.25 sp. gr. To a measured amount of this solution add 4 volumes of water and 

 filter if not perfectly clear. The solution should be standardized each time a set 

 of determinations is made. 



If the directions for preparing the basic lead acetate are not carried out care- 

 fully, the use of Home's dry basic lead acetate is preferable. 



64 DETERMINATION OF LEAD IN THE BLANK. 



Transfer 25 cc. of the standard basic lead acetate to a 100 cc. flask, add a few drops 

 of acetic acid, and make up to the mark with water. Shake and determine lead 

 sulphate in 10 cc. of the solution as directed under 65. The use of the acid is im- 

 perative in this case to keep the lead in solution, when diluted with water. 



65 DETERMINATION. 



Transfer 25 grams of the sample to a 100 cc. flask by means of water. Add 25 

 cc. of the standard basic lead acetate and shake, fill to the mark, shake, and allow to 

 stand for at least 3 hours before filtering. Pipette 10 cc. of the clear filtrate into 

 a 250 cc. beaker, add 40 cc. of water and 1 cc. of concentrated sulphuric acid, shake 

 and add 100 cc. of 95% alcohol. Allow to stand overnight, filter on a tared Gooch, 



