Issued March 9, 1910. 



United States Department of Agriculture, 



BUREAU OF CHEMISTRY Circular No. 53. 



H. W. WILEY, Chief of Bureau. 



SUGGESTED MODIFICATION OF THE WINTON LEAD NUMBER, 

 ESPECIALLY AS APPLIED TO MIXTURES OF MAPLE AND CANE 

 SUGAR SIRUPS. 



By S. H. Ross, 

 Acting Chief, Omaha Food and Drug Inspection Laboratory. 



APPLICATION OF THE ORIGINAL METHOD TO KNOWN MIXTURES. 



The lead number as originally devised by A. L. Winton a was in- 

 tended to distinguish pure maple sirup from mixtures containing cane 

 sugar sirup. The practice of adopting a standard lead number for 

 pure maple sirups and then calculating the percentage present in a 

 given mixture or compound sirup from the lead number obtained 

 thereon is questionable. The value of the lead number for this pur- 

 pose can be readily determined by tests made on mixed sirups of 

 known composition. 



At the suggestion of Doctor Winton, a preliminary test was made 

 by the writer in the Chicago laboratory. The lead number was 

 determined on two sirups: A, an alleged pure maple sirup, and B, 

 a mixture of 50 per cent by weight of A and 50 per cent by weight 

 of a cane sugar sirup of the same specific gravity. The lead number 

 on A was 0.90 and on B only 0.29, instead of the theoretical 0.45. 

 The apparent percentage of the maple sirup A in this mixed sample 

 was, therefore, approximately 32 per cent instead of 50 per cent, 

 which was actually present. The following study of this point was 

 made at the Chicago laboratory: 



Sirups C and D, containing 65 per cent of solids, were made from 

 two supposedly pure samples of maple sugar. Another sirup, S, 



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

 24490 Cir. 5310 



