7. Alkalinity of soluble ash. 



8. Alkalinity of insoluble ash. 



9. Ratio of insoluble ash to soluble ash. 



Other determinations that might be made if the analyst deemed it 

 advisable are: 



10. Reaction with iodin after decolorizing with charcoal. 



11. Polarization before and after inversion at 87. 



12. Malic acid value. 



13. Percentage of calcium oxid (CaO), potassium oxid (K 2 O), and sulphur trioxid 

 (SO 3 ) in the ash. 



METHODS OF ANALYSIS. 



The methods for making these determinations are given in the 

 order in which they have been enumerated, and in connection with 

 each method the average figures obtained by it for pure maple sugar 

 and sirup, based on the published works of Jones, Hortvet, and Win ton 

 and on about sixty samples analyzed in 1904 and 1905 in the Bureau 

 of Chemistry, are stated. 



I. PER CENT OF MOISTURE AND DRY SUBSTANCE. 



(a) Determine loss of weight by drying 4 grams of the sample on sand in a vacuum 

 oven at 70 C. to constant weight. 



(6) Add 100 grams of water to 100 grams of sirup and obtain the degrees Brix with 

 a Brix hydrometer. Then multiply this by 2 and subtract from 100 to obtain the per 

 cent of water. 



(c) Find the refractive index of the sirup at 20 with an Abbe heatable prism 

 refractometer and consult tables of Geerlig in the International Sugar Journal, Feb- 

 ruary, 1908, page 69, or in the Journal of the American Chemical Society, Septem- 

 ber, 1908. The per cent of moisture is obtained by subtracting the per cent of dry 

 substance from 100. 



The Food Standards 65 allow not more than 32 per cent of water 

 in maple sirup, which would be equivalent to a specific gravity of 

 1.3383. No standard water content is set for maple sugar. Hortvet 

 publishes figures for water content of pure maple sugar varying from 

 4.27 per cent to 15.67 per cent, giving an average of 8.85 per cent. 



II. POLARIZATION AT 20 C. 



Make up the normal weight (26 grams) of the sample to 100 cc (true) in a flask. 

 If the original substance is too dark to read easily, clarify with lead subacetate. 

 Polarise in a 200 mm tube. Free 50 cc of solution from lead by treating with an- 

 hydrous sodium carbonate or neutral potassium oxalate and invert by either method 

 described in Bulletin 107, Revised. & Make the reading in a 200 mm tube, correct 

 for dilution, and calculate the percentage of sucrose by the following formula: 



_ 100JP- 1) 

 ~" 142.66 - T 



U. S. Dept. Agr., Office of the Secretary, Cir. No. 19, p. 10. 



& U. S. Dept. Agr., Bureau of Chemistry, Methods of Analysis, Bui. 107, Revised, 



p. 40 (c). 



[Cir. 40] 



