Hortvet gives the following figures for pure maple sugars: 



Direct polarization (V.)-- +72.6 to +87.4 



Invert polarization (V.)__ 31.0 to 27.2 



Sucrose by Clerget method (per cent). _ 80.20 to 89.53 



For pure maple sirups : 



Direct polarization (V.) _ +51.0 to +62.2 



Invert polarization (V.) 25.6 to 20.0 



Sucrose by Clerget method (per cent) _ . 53.29 to 65.11 



III. REDUCING SUGARS. 



This determination can be made on a portion of the lead-free solution obtained 

 from Method II, but it would be better in case much reducing sugar is present to 

 make up 5 grams of the sample to 100 cc, clarifying with about 1 cc of neutral lead 

 acetate. After filtering, remove the lead with anhydrous sodium carbonate or potas- 

 sium oxalate. Determine the reducing sugars in 25 cc by the Munson and Walker 

 method," or by the Allihn method. & The reducing sugar should be calculated as 

 invert sugar, as given in Munson and Walker's table; or, if Allihn's method is used, 

 multiply the percentage of dextrose by the factor 1.044 to obtain the per cent of in- 

 vert sugar. For accurate determinations of reducing sugar in maple sugar, use 

 Meissl and Killer's table, or with Munson and Walker's method prepare the sugar 

 solution of the strength given in either of the two columns headed "Invert sugar and 

 sucrose." 



In nineteen samples of pure maple sugar analyzed by Hortvet, 

 eleven samples were below 3 per cent, three samples between 3 and 

 4 per cent, and two samples between 4 and 5 per cent. The remain- 

 ing three samples were above 5 per cent. The highest result obtained 

 was 8.37 per cent. 



Among twenty-two samples of pure maple sirup analyzed by 

 Hortvet, ten were below 2 per cent, five between 2 and 3 per cent, 

 three between 3 and 4 per cent, and two between 4 and 5 per cent. 

 The highest result was 9.17 per cent. 



IV. LEAD NUMBER (wiNTON). d 



For this determination a standard lead subacetate solution must 

 be prepared according to the following directions: 



Standard lead subacetate solution. Boil for one-half hour 430 grams of normal lead 

 acetate and 130 grams of litharge with 1,000 cc of water; cool the mixture; allow to 

 settle, and dilute the supernatant liquid to 1.25 specific gravity. To a measured 

 amount of this solution add four volumes of water and filter if not perfectly clear. 



J. Amer. Chem. Soc., 1906, 28: 663-686; U. S. Dept. Agr., Bureau of Chemistry, 

 Bui. 107, Revised, p. 241. 



& U. S. Dept. Agr., Bureau of Chemistry, Bui. 107, Revised, p. 49-51. 

 Ibid., p. 44. 



d J. Amer. Chem. Soc., 1906, 28: 1204. 

 [Cir. 40] 



