654 The Philippine Journal of Science 1922 
is true in total dry matter, the difference, however, being insig- 
nificant (Table 11). 
From the results with the single crop grown in shaded and 
unshaded chambers we find (Table 21) that the shaded plants 
have higher average percentages of ash in stems and leaves and 
lower percentages in roots than the unshaded ones. The total 
dry matter (Table 22) of the unshaded plants was higher, owing 
probably to the difference in relative rates of carbon dioxide 
assimilation, but in percentage of total ash the difference, which 
is very significant, is in favor of the shaded plants. 
In Tables 16 and 22 the amount of water transpired by individ- 
ual plants in the period of four weeks is placed side by side 
with the amount of total dry matter and percentage of total ash 
in each plant. Assuming that the relative amounts of water 
transpired in four weeks of the crops’ lifetime is a fair index 
of the total amount of water transpired in the whole life period 
of the crops, the data in Tables 16 and 22, whether only for 
plants grown in humid or shaded atmosphere or only for those 
grown in dry or unshaded rooms, should furnish an indication 
as to whether or not the absorption of mineral salts is directly 
proportional to the relative rates of transpiration. In Table 16 
it will be seen that in the humid crops the plant which transpired 
the greatest amount of water in four ‘weeks did not have the 
greatest amount of dry matter or the highest percentage of 
ash; neither did the plant with the lowest transpiration have 
the lowest dry weight or percentage of ash. The same is true 
with the crop grown in the dry chamber. In the shaded and 
unshaded crop, the plants having the lowest transpiration had 
the least dry weights, but not the lowest percentages of ash; 
those with the highest amounts of transpired water again did 
not have the largest percentages of ash or the largest amounts 
of dry matter. In Tables 17 and 23 the amount of dry matter 
and ash corresponding to 100 cubic centimeters of water tran- 
_ Spired are given. For 100 cubic centimeters of transpired water 
we see that the “humid” or “shaded” plants average higher in 
absolute weight of ash and dry matter. 
CONCLUSION 
The results of the present experiments show that in tobacco 
plants grown in water culture, there was no absolute correlation 
between the percentage of ash, the relative rates of transpiration, 
and the total dry matter. 
