8 



and 10, which had been flowing since March 22 from holes i^ 

 inches deep, were then bored to a depth of 2^- inches in the same 

 holes on April 9. Samples of sap from each tree were taken 

 before and after the increase in depth of holes. The results 

 were the same as with tree 13, and furthermore, the percentages 

 of sugar continued to remain higher for the balance of the sea- 

 son than they were before the experiment. 



On April 20 two more trees, o and/, were tapped by boring a 

 hole of large diameter to the depth of i inches and then con- 

 tinuing with one of small diameter to an additional depth of 2 

 inches. The sap was collected from the outer and inner wood 

 by means of a double spout consisting of one tube within an- 

 other. The results this time agreed with the above claim. 



In 1894, two trees, r and s, were tapped in a similar manner, 

 with the exception that the outer hole was carried to a depth of 

 2^5 inches, and the inner hole 2^ inches further. Again the 

 results agreed with the claim. 



VARIATION IN COMPOSITION OF SAP FROM OUTER AND INNER 

 WOOD. 1893. 



