538 
Journal of Agricultural Research 
Vol. V, No. 12 
In the leaf the silica, sodium, magnesium, and phosphorus are uni¬ 
formly lower than in 1912 and the organic matter and potassium are 
higher, while the other constituents vary both above and below the 
former results. In the stem, however, the organic matter, sodium, and 
phosphorus are lower than formerly and the iron, al uminum , calcium, 
magnesium, potassium, and sulphur are higher, while the silica is variable. 
Another interesting point is that most of the results show that the 
mineral constituents are lower in the leaves of this year (1915) than 
formerly, while in the stem they are higher. 
The ratios of calcium oxid to magnesium oxid and potassium oxid 
to sodium oxid in the leaf and stem below show, as did those of the sap, 
that the former is more constant than the latter (Table XVI). 
Tabu; XVI .-^-Comparison of ratios of calcium oxid to magnesium oxid and potassium 
oxid to sodium oxid in leaves and stems of young wild-grape vine in the same and in 
different years 
Part and sample IsTo. 
Ratio of 
calcium 
oxid to 
magnesium 
oxid. 
Ratio of 
potassium 
oxid to 
sodium 
oxid. 
Leaf: 
627 . 
908 . 
5 ’ 4 • * 
it A • T 
y* u * 1 
33 - <5 : 1 
0*1 ft * T 
910 ... 
4. 9 . x 
e *7 • t 
912 . 
5 * 7 • 1 
c e * r 
^y. 0 . I 
21. 5 :1 
914 . 
5 * 5 * i 
A T * T 
Stem: 
628 . 
2 n • t 
20* 011 
909 .. . 
O* 2 • 1 
O A • r 
22. 7 : i 
911 . 
2. 9 . I 
61. 7 • i 
913 . 
. 3 * 5 • 1 
A A * T 
30. O . I 
30. 7 : i 
f j ft * T 
915 . 
4. 4 . x 
5 a • r 
3. 2 . I 
54 * 0 * I 
EXPERIMENTS WITH SUGAR MAPLE 
Having found such a wide variation in the composition of the sap of 
the wild-grape vine, it was thought that it might prove of further in¬ 
terest to compare the analyses of the sap of the same sugar-maple tree 
(Acer saccharum) collected during two successive years. Accordingly, 
early in 1913 and 1914, just after the sap began to rise, samples were 
collected at the same point on the tree, about 3 feet from the ground. 
Also, for a further comparison, the sap was collected in 1913, just 
after the sap flow commenced, from a water-maple tree (Acer sac- 
charinum) at a point about 10 feet from the ground. 
The results are given in Tables XVII and XVIII. 
