16 MAPLE-SAP SIRUP. 



The Lovibond tintometer with brewer's scale was tried, but its use was found to 

 complicate the determination, as with the light-colored sirups an inch cell could be 

 used, but with the ordinary colored sirup a one-eighth inch cell was necessary and the 

 darker colored sirups could not be read at all. It seemed best, therefore, to use these 

 standard colors which are easily prepared, and when the caramel solution is made as 

 prescribed an even color is obtained. An attempt has been made in the color chart 

 (see Plate I) to reproduce these as they appear by transmitted light. This chart 

 should be used only for an approximate determination and for relative values; for an 

 exact classification the colors should be prepared as described and a direct comparison 

 made. 



MOISTURE. 



The refractometer and the table of Geerligs were used, it having been proved that 

 this method gives results concordant with those obtained by actual drying. 



POLARIZATION. 



Weigh out accurately 26 grams of the sirup and transfer to a 100 cc flask (true cc) with 

 water. (In most cases 5 cc of alumina cream were added and the contents made up to 

 the mark. In the few instances when it was necessary to clarify with lead, 1 cc 

 of neutral lead acetate was used.) After filling to the mark add about 1 gram of dry 

 kaolin and shake to give a clear solution on filtering. Determine the direct polariza- 

 tion at 20 C. Place 50 cc of the solution in a 50 to 55 cc flask (if lead is present remove 

 it with a small quantity of dry potassium oxalate), add 5 cc of concentrated hydro- 

 chloric acid, and allow to stand for over twenty-four hours, at the room temperature, for 

 inversion. On the following day make polarizations at 20 and 87 C. on this solution. 



In this investigation the solution was not neutralized before heating to 87 as the 

 arrangements for conducting the determination were such that the solution was not 

 heated for more than one or two minutes before the reading was made. Sucrose was 

 calculated from the formula 



q_100 (P-I) 



~TT 



142.66-2- 



INVERT SUGAR. 



Munson and Walker's method and tables & were used for this work. Make up 50 cc 

 of the sugar solution required by adding 10 or 15 cc of the solution used for polarization 

 to 35 or 40 cc of water. Weigh the precipitated red oxid as such and find the quan- 

 tity of invert sugar present from the table in the column headed, "Invert sugar and 

 sucrose, 2 grams total sugar. " Allowance is thus made for the reducing effect of the 

 sucrose on the Fehling solution. Fifteen cubic centimeters of the solution for polariz- 

 ing (3.9 grams of original sirup) contain about 2.43 grams of total sugars. If the per- 

 centage of invert sugar present is not over 6 per cent, which is the case in many fresh 

 samples, use 15 cc, but if more is present, 10 or even 5 cc should be used. When using 

 as little as 5 cc it would be better to use the value for invert sugar found in the column 

 headed, " Invert sugar and sucrose, 0.4 gram total sugar." 



ASH DETERMINATIONS. 



Total ash. Weigh out 5 grams of the sirup in a tared platinum dish, add a few 

 drops of pure olive oil to allay frothing, and heat the whole carefully over the direct 

 Bunsen flame. When this is thoroughly carbonized place the dish over a low-burning 



U. S. Dept. Agr., Bureau of Chemistry Cir. 43, p. 7; Bui. 122, p. 169. J. Amer. 

 Chem. Soc., 1908, 30 : 1443-51. 



&U. S. Dept. Agr., Bureau of Chemistry Bui. No. 107, Revised, p. 241. 



