42 



HAEEINGTON ON THE SAP 



was 2.7*7 oil the 11th of the month, the lowest 1.98 on the 8th. The average for the first 

 six days was 2.38 per cent., and for the last six days 2.26 per cent. Ou looking at the 

 tables it will also be seen that, as might be expected, there is a close correspondence 

 between the density of the sap and the contents of sugar. 



Table III. — Negundo aceroides. (Male.) 



In a few instances, 20 c.c. of the sap were evaporated in a platinum dish until the 

 sugar began to darken from incipient decomposition, and the proportion of residue or 

 crude sugar obtained in this way was found to be about 0.4 per cent, higher than that of 

 the sugar as indicated by the polariscope. A somewhat similar result was also obtained 

 by evaporating larger quantities of sap, thus : — 



Table IV. 



