1918] Nichols & St. John,— Corrugated Boards 159 
alone by the second and fourth. As to the relative merits of s. f. 
ventilators plus driers versus d. f. ventilators, it should be said that 
the results obtained with the former of these two equipments are quite 
equal to those obtained by the latter, but the first, third, fourth and 
fifth factors mentioned above are all in favor of the d. f. ventilators. 
Using the first equipment it takes several days to dry a load of plants, 
while with the second a full capacity load can be turned out each day. 
In this connection it should be remarked that the “Washington” 
drier is far superior to the ordinary type in its greater absorbent 
power, thinness, firmness, and strength. So far as bulk and actual 
weight are concerned, equal quantities of s. f. ventilators plus driers, 
on the one hand, and of d. f. ventilators, on the other, are about 
equally matched: one hundred d. f. ventilators were found to weigh 
28} pounds, as compared with 153 and 13% pounds for the same 
quantities of s. f. ventilators and Washington driers respectively. 
But the great saving in both bulk and weight is seen when account 
is taken of the speed with which results can be obtained by using the 
d. f. ventilators. On an extended collecting trip a given number of 
d. f. ventilators will turn out as many dried specimens as three or 
four times their number of s. f. ventilators plus driers. Add to this 
the greater convenience in handling and the superiority of the d. f. 
ventilators can hardly be questioned. 
With regard to the use of artificial heat, it is our opinion, based on 
several years’ experience, that so far as the quality of results is con- 
cerned no potent objection can be urged against it: on the contrary, 
as earlier indicated, the specimens dried in this way are obviously 
superior to those dried without heat. Moreover the saving of time 
and energy and, in the field, of weight and bulk are big items. As to 
the source of heat, for field work either a lantern or a fire is satis- 
= factory. It must be admitted, however, that a fire does require more 
- or less constant attention, and that on this account, where it is 
practicable, a lantern is to be preferred, since, while it does not pro- 
duce results quite as rapidly, the lantern requires much ipes super- 
vision and can be left on duty day and night. 
For use in the laboratory the senior writer has found great satis- 
faction in the following equipment. A rectangular wooden box about 
three feet high and open at the top was constructed. The width of the 
box is slightly more than the length of a pressing frame; its length 
is immaterial, but is sufficient to accommodate a press about two feet 
