until solution is complete. Cool and titrate with tenth-normal sodium hydroxid, 

 using methyl orange as an indicator. Subtract the number of cubic centimeters of 

 tenth-normal alkali used from the number of cubic centimeters of acid and the 

 remainder will be the number of cubic centimeters of acid used to neutralize the 

 insoluble ash. Divide this number by 5 and the result is the alkalinity of insoluble 

 ash expressed in terms of the number of cubic centimeters of tenth-normal acid 

 necessary to neutralize the ash of a 1-gram sample. 



Pure maple sugar cc of acid necessary to neutralize 1 gram: 



Jones _ 0.55 to 1.72; average, 0.91 



Hortvet 0.66 to 1.46; average, 1.06 



Pure maple sirup cc of acid necessary, to neutralize 1 gram: 



Jones__ _ 0.36 to 0.94; average, 0.54 



Hortvet 0.32to0.79; average, 0.61 



Bureau of Chemistry 0.31 to 0.92 ; average, 0.52 



IX. RATIO OF INSOLUBLE ASH TO SOLUBLE ASH. 



This ratio is found by dividing the second result (percent soluble ash) 

 obtained under determination VI by the first (per cent insoluble ash) . 



Pure maple sugar ratio of insoluble to soluble ash: 



Jones 0.5 to 2.2; average, 1.1 



Hortvet I _ 0.5 to 1.4; average, 0.9 



Pure maple sirup ratio of insoluble to soluble ash: 



Jones 0.7 to 2.6 ; average, 1.7 



Hortvet _ _ 0.7 to 2.5 ; average, 1.4 



Bureau of Chemistry 0.6 to 3.2 ; average, 1.8 



X. REACTION WITH IODIN. 



This test need only be applied when glucose is suspected to be pres- 

 ent. The procedure is that outlined by Beckmann: 



Prepare a solution of the suspected sirup with an equal quantity of water; if dark 

 in color, place a quantity of powdered animal charcoal in the tube and shake; allow 

 to stand for a little while, and then filter. The resulting solution should be nearly 

 colorless. To this is added a few cubic centimeters of iodin solution (iodin in potas- 

 sium iodid). If glucose is present, the solution turns red or violet, the depth and 

 character of the color depending upon the quantity and nature of the glucose employed 

 for adulteration. A blank test with a pure sirup, using the same quantity of iodin 

 solution, should be made at the same time for the purpose of securing an accurate 

 comparison of color. 



XI. POLARIZATION AT 87. 

 



This test need not be made unless glucose is suspected from the results of previous 

 determinations or when commercial dextrose is supposed to have been added. It is 

 based on the fact that at 87 invert sugar is optically inactive. Hence any positive 

 rotation observed at this temperature is due to the presence of some optically active 

 bodies other than invertsugar. The polarizations should be made in a jacketed 

 silver tube, and in case of the polarization of invert solutions the acid should be just 

 neutralized before trying to polarize. A strong right polarization of the invert solu- 

 tion is an indication of glucose. For determining the approximate amount of glucose 



Zts. anal. Chem., 1896, 55:267. 

 [Cir. 40] 



