224 THE ROYAL SOCIETY OF CANADA 



and Warren^ have made vague conjectures, and I have been told that 

 a Canadian chemist once satisfied himself as to the constitution of 

 the flavouring material but did not publish his work. The identifica- 

 tion of this substance and the invention of a quantitative test for it 

 would be a notable achievement. 



Syrups skilfully made from fresh maple sap are very light-col- 

 oured and there is no definite evidence that the sap contains any 

 specific pigment. Deterioration of the sap by micro-organic action,^ 

 caramelization of sugar in the evaporator and the action of adventi- 

 tious tannin^ on the iron of untinned evaporators may be the true 

 sources of the light yellow to deep red and brown colours observed in 

 the less carefully made syrups and sugars. 



Ash analyses^ indicate clearly that potassium and calcium salts 

 of organic acids are the leading non-sugar constituents of maple 

 syrup, with magnesium and sodium salts and silica also fairly prom- 

 inent and some sulphur compound usually present.^ 



The only complete ash analyses as yet published are four by 

 Hortvet and one of a composite of 60 syrups made by Mr. J. M. Scott 

 in this laboratory. Mr. Van Zoeren has analyzed the ash of five 

 syrups about which we have very full information as to origin, analytical 

 values, etc. Averaging these five analyses with Hortvet's four and then 

 averaging the result with Mr. Scott's on equal terms we get: K2O, 

 29-45; NasO, 2-99; CaO, 23-24; MgO, 4-29; FcsOs, 1-31; MnaO^, 

 0-90; COo, 32-08; SiOa, 2-75; .P2O5, 0-63; SOg, 1-46; CI, 1-05. 

 Sum-0-equiv. of CI ( = 0-24), 100-21-0-24 = 99-97. 



Jones^ has published determinations of lime, potash and sul- 

 phuric acid in ten samples with results averaging nearly the same as 

 the above. Bryan'' determined the same three constituents and phos- 

 phoric acid in 100 syrups, obtaining decidedly higher results on potash 

 and phosphoric acid than have been found by the other analysts. 



With what organic acid the metals are combined has not been 

 clearly elucidated. Mr. Van Zoeren has made some attempts to 



^Vermont Maple Sugar Makers' Association, Twentieth Annual Report (1913), 

 p. 50-1. 



2 Edson, Vermont Agr. Expt. Station, Bulletin 167 (1912). 



3 Bryan, U.S. Dept. Agr., Bureau Chem. Bull. 134 (1911), p. 66; U.S. Dept. 

 Agr. Bull. 466 (1917), p. 34-5. 



< Horvet, Journ. Am. Chem. Soc, 26 (1904), 1541: Jones, Vermont Agr. Expt. 

 Station, Eighteenth Annual Report (1904-5) 331: Bryan, Bureau of Chem., U. S. 

 Dept. Agr. Bull. 134 (1910), 82-89; Snell, Journ. Ind. Eng. Chem., 8 (1916), 146. 



* Seven of Bryan's 100 ash samples were sulphate-free. 



6 Vermont Agr. Expt. Station Eighteenth Annual Report (1905), p. 331. 



7 U.S. Dept. Agr. Bull. 134 (1911), p. 82-89. 



