1917] 
ZELLER—DURABILITY OF YELLOW PINE 147 
only 0.028 per cent, while the adjoining block, Е 1604, was 
reduced 17.5 per cent; also G 1603 was reduced 0.14 per cent 
and G 1604 was reduced 17.4 per cent. Many other examples 
in table 1 could be given. 
Another discrepancy in the data is the one already men- 
tioned concerning the loss of resin in sterilization. The charts 
bring out this discrepancy very vividly. Take, for instance, 
the charts correlating resin content and specific gravity with 
percentage loss in weight during one year of incubation. If 
we consider here that a part or all of the loss in weight above 
17.6 per cent resin is due to sterilization and that above a 
specific gravity of .70 to .75 (the average for longleaf pine) 
the extra weight is due to an excess of resin, the charts will 
at once show the error due to sterilization. In the general 
chart showing the relation of specific gravity to the percent- 
age reduction in weight this is more evident than in the other 
charts. In this chart the values of the specific gravity are 
marked off on the primary ordinate, and the percentages of 
reduction in weight on the primary abscissa. Аз the specific 
gravity increases above .70 to .75 the curve formed by the 
plotted points gradually swings away from the primary ordi- 
nate. An examination of representative samples in this part 
of the chart reveals the fact that they have not been attacked 
in the least by the fungus. We are safe, then, to assume that, 
as far as loss of weight due to decay is concerned, the plotted 
points in this part of the chart can be moved over toward the 
primary ordinate. 
Thus, these two factors, (1) the chance of failure of infec- 
tion and (2) the loss of weight of highly resinous blocks due 
to sterilization, must be considered when attempting to draw 
conclusions from the various charts. 
CHARTS BASED ON THE RESULTS OF SERIES A 
In the charts plotted from the data obtained in series A 
the three species of pine are distinguished by symbols de- 
scribed in the keys of the various charts. A bar drawn through 
any of these symbols represents sap-wood. 
