262 
straiten yourself in this respect, for a good pile of surplus driers never 
comes amiss on returning from a fruitful botanical excursion, nor 
during a period of cloudy weather. ‘These remarks are equally 
applicable to specimen paper, which I described and insisted on under 
“ Outfit.” Lay in sufficient stock of this paper before the collecting 
season opens, as you can buy it much cheaper in quantity. By a 
rough estimate from the writer’s experience, nearly half as many 
specimen sheets, for the season, will be required, as the number of . 
specimens to be pressed, in that period: if you expect to dry 5,000 
specimens during the season, you will generally want about 2,50 
sheets to do it with. Less new stock will be required each success- 
ive year, as the old sheets, out of which the specimens were taken 
in winter for mounting and exchanges, are good for the coming 
season. 
” Next provide yourself with a dozen or more pieces of board, 18 
inches long and 12 inches wide. ‘They are used at the top and bot- 
tom of the pile when pressing, and also for dividing the pile into 
suitable divisions,—separating the packages of plants which were 
put in press at different periods, and dividing up the packages them- 
selves if too large. Painted binder’s-boards may be used instead of 
common boards if more convenient to obtain. Instead of either of 
these, some collectors use a kind of lattice arrangement, the size of 
the driers, made of two layers of thin strips or laths, nailed . across 
each other. They claim that it permits the circulation of air in the 
piles and so hastens drying. But when the driers are changed regu- 
larly, I have been unable to find any especial advantage in its favor. 
For giving pressure various ways have been contrived. The 
screw press is convenient and compact, but otherwise objectionable, 
for, although we may give the correct amount of pressure at the out- 
set, (but in fact it is generally too great at first,) yet, as the plants 
shrink in drying, they will fail to receive the required pressure. This 
objection does not apply to the lever press, but all that the writer 
has ever seen, are unwieldy and inconvenient. It is possible, how- 
ever, some forms of this press might be used with advantage by our 
less muscular botanists, as it could be so arranged that ro or 15 lbs. 
might be made to give a pressure of 50 to too lbs. 
Fortunately one of the best forms of the drying press, as well as 
the simplest and cheapest, is merely a board with weights placed 
upon the top of the pile of specimens. Here, by the simple gravita- 
tion of the weights on top, the pressure is continued, and constantly 
follows up, or rathet dows, the shrinkage of the plants. The weight 
on a pile should vary from 25 to roo lbs., according to nature of the 
specimens and the quantity in the press at the time. Onan average 
60 lbs. is sufficient for most plants,—rarely should it exceed 75 lbs. ; 
with more than this there is danger of crushing the more delicate 
parts of the flower especially, and’consequently impairing the scien- 
tific value. Plants requiring most pressure may be placed at the 
bottom of the pile, where, in addition to the regular weight, they will 
have that of the pile above them. From an erroneous idea that the 
colors are better preserved by using great pressure, some botanists 
are in the habit of applying as high as 200 Ibs. weight to their spec- 
