On the Unit of Linear Measurement. By Rev. D. Edwardes. 49 
(Lesquereux). Green County, Mississippi (Tice). New Jersey 
(Austin). 
Quite peculiar among the Sphagna, by the uniform branches in 
the fascicles, the slender pendent branches found in most of the 
species being wanting, and also by the central position of the pores 
and total absence of fibrils. The convolute leaves and pointed 
branches give it somewhat the aspect of Hypnum cuspidatum, 
while if we overlook the pores, the areolation is not unlike that of 
II. riparium or fluitans, and with this approximation to the true 
mosses we conclude our series of Sphagna. 
EXPLANATION OF PLATE CXI. 
Sphagnum macrophyllum. 
а. — Fertile plant from Drummond’s collection. 
4. — Perichcetial bract. 4 p. — Point of same. 
/>. — Stem leaves. 5 a a. — Areolation of same. 
б. — Leaves from middle of a branch. 6 p. — Point of same. 6 x. — Section. 
G c. — Cell from middle x 200. 6 b. — Leaves from base of the same 
branch. 
9 x. — Part of section of stem. 
10. — Part of a branch denuded of leaves. 
III. — On the Unit of Linear Measurement. 
By Bev. D. Edwardes, M.A., St. Chad’s College, Denstone. 
Beading Schumann’s ‘ Diatomeen der Hohen Tatra ’ a short time 
ago, I came across the following passage : “ Auch die Englander 
werden auf dem Felde der Diatomeen den englischen Zoll, wenn- 
gleich er durch die experimentalen Arbeiten Newton’s eine beson- 
dere W eihe erhalten hat, aufgeben und mit dem Maase Ehrenberg’s 
messen.” This was written in 1867. I immediately set to examine 
a few of the last volumes of the Microscopical Journal, as being 
the best test I could think of as to what extent the event of things 
has proved Schumann’s prophecy true. I founJ, as I expected, 
scarcely an instance of an English microscopist making use of the 
Paris line, which was Ehrenberg’s standard unit. 
Although English microscopists are thus still sturdy English- 
men, yet there is a large number of English men of science who 
seem to think that wisdom is found only on the other side of the 
Channel, and are endeavouring to further in this country the 
arbitrary introduction of the French system of measurement. 
I have no wish to predict what will be the system of measure- 
ment fifty years hence, but it does seem to me that both parties — 
the English and the French — are content to put up with a more im- 
