— 6i — 
an envelope has been removed, and even then is not much greater than that 
caused by several pin holes and the accompanying wrinkles in the paper. 
To the writer the only real argument against the use of the wafer lies in the 
fact that when an attached envelope is grasped by the edges and lifted away 
from the paper (a condition which never ought to occur, perhaps, in a care- 
fully handled herbarium) the watered envelope is — as is shown by tests — much 
more easily detached than the pinned one : the ratio of energy required to 
detach it being 16. To offset this, when an attempt is made to detach an 
envelope by pulling it along the surface of -the sheet without lifting it, the 
watered one necessitates more than twice the energy required by the pinned 
one (7:3). The advantage is also most decidedly with the watered envelope 
(10-15:1) when a twisting strain is applied. 
Some of the obvious advantages in using wafers— when compared with 
pins — are as follows: The envelope does not have to be opened when it is 
being fastened to the sheet, nor during its removal ; the watered envelope is 
more quickly and easily fastened, and its removal is even more quickly 
accomplished : the wafers cost considerably less than the pins : neither paper 
nor envelope is perforated : the back of the sheet is smooth, with no pin 
shanks to rub specimens beneath. Although the pin shanks rarely harm 
specimens beneath, the danger of their doing so exists nevertheless. 
In a moss herbarium which is to be constantly consulted there are obvi- 
ous advantages in having a portion of each specimen mounted on the herbar- 
ium sheet, outside the envelope. Much time, which would otherwise be 
utilized in opening and closing envelopes, is thus saved. This is really quite 
an item when one’s time is all' too limited, and a hand-lens examination of 
several or many specimens becomes necessary or desirable. The writer’s 
method of mounting such specimens is not essentially different from that in 
common use for mounting seed-plants in most of the large herbaria. Liquid 
glue is brushed in a thin layer over a plate of glass. For mosses this glass 
need not necessarily be larger than 6 x 8 or 8 x 10 inches. Into this film of 
glue the specimen is pressed until the glue touches the essential portions of 
the under surface of the specimen. The latter is now lifted with forceps and 
laid on the mounting sheet in the position desired, and finally a suitable 
light pressure applied until the glue sets. A few words of caution to those 
who have never used this method for mounting mosses may be helpful. The 
commercial liquid glue should be diluted more or less, as experience dictates, 
with either water or vinegar — about -equal parts of glue and vinegar is the 
proportion commonly used by the writer. It must be borne in mind that water 
and vinegar moisten the moss and often cause more or less of a change from 
the typical dry state in such parts as come in contact with either fluid. Con- 
sequently, care should be taken to allow only the lower surface of the speci- 
men to touch the glue-covered plate. It is almost equally important not to 
allow the specimen to remain in contact with the glue longer than required 
to touch the desired parts, as otherwise there is danger that the glue will 
creep or filter through to the upper surface of the specimen — not only moisten- 
ing that surface but often leaving unsightly films or spots. This is a simple 
