1G 



The results obtained in these studies upon the flow of sap 

 are in accord with the observations of Professor Wood reported 

 in Bulletin 24 and add force to his conclusion that more sap 

 flows from a deep hole than from a shallow one. The exact 

 depth to which the hole should be bored is unsettled and may 

 prove to depend upon the size of the tree. 



The longer flow of sap from the inner wood of numbers 10 

 and 12 agrees with the practice of retapping trees toward the 

 close of the season. 



The results obtained b} T studying the composition of the sap 

 from different depths in the tree, are still contradictory, as was 

 shown in Bulletin 25 ; inasmuch as two trees yielded the richer 

 sap from the outer wood and one from the inner wood. The 

 results, however, are in accord with the statement that the more 

 sap there is produced by a tree, the greater is its yield of sugar. 



The glucose (reducing sugars) and ash were determined 

 several times in the samples from numbers 8 and 11, but the 

 difficulties in the way, prevented a continuity of results. How- 

 ever, figures were obtained from samples distributed through 

 the season and including the last ones. The sap contained such 

 minute quantities of both substances that it was found uecessary 

 to evaporate a weighed quantity to a thin syrup, determine the 

 glucose and ash in this and calculate back to the original. 



Nine estimations of glucose were thus made in the case of 

 each of the trees. The results from number 8 ranged from 

 0.0042 to 0.0097 percent with an average of 0.0075 per cent. 



Number 1 1 showed higher results, the range being from 

 0.0051 to 0.0244 per cent and the average 0.0123 per cent. 

 The highest results were obtained in the early part of the sea- 

 son, instead of from the last runs. 



Ten estimations of ash were made in the samples from num- 

 ber 8 and twelve in those from number 11. The range in the 

 former was from 0.029 to 0.114 per cent and in the latter from 

 0.038 to 0.087 per cent. The average percentage was almost 

 the same in both being 0.051 and 0.052 respectively. 



The soil in this vicinity is a clay loam with clay subsoil and 

 overlies granite ledges. 



