content). The first three samples (E, Ohio; F, Vermont; and G, 

 Canada) were authentic. The fourth sample (H) was unknown, but 

 was used to illustrate the variation of the lead numbers obtained on 

 mixtures made from a sirup having a low lead number. All of the 

 results given in the following tables are on the basis of the acid 

 blank: 



Winton lead numbers on known mixtures, using the acid blank. 



These results show conclusively that the lead number thus 

 obtained is not proportional to the amount of maple sirup present 

 in a mixture. Theoretically a pure maple sirup, which gives a 

 copious precipitate when treated in the usual manner, should yield 

 one- tenth the volume of the original precipitate if it is first diluted 

 with 90 per cent of inert cane sugar sirup. But in several instances 

 it was observed that these 10 per cent maple content sirups gave no 

 precipitate or at most an opalescence, which would be reported as 

 "no precipitate" or "slight precipitate," and the sirup would be 

 declared ordinarily to contain little or no maple sirup. 



INFLUENCE OF SUCROSE AND LEAD SUB ACETATE ON THE MAPLE 



LEAD PRECIPITATE. 



As a deduction from these experiments, it was inferred that the 

 nonproportional result obtained on a mixed maple and cane sugar 

 sirup was due to the solvent action of the sugar solution which par- 

 tially inhibited the formation of the maple lead precipitate. Doo- 

 little and Seeker a judged that this discrepancy was due to a great 



U. S. Dept. Agr., Bureau of Chemistry Bui. 122, p. 198. 



[Cir. 53] 



