ee - 
80 Prof. Kekaaail some > Ferns of the United States. ‘ 
boilers were ten ‘be: pacme might be passed un- 
and ret _under Gk; A ap oven might 
upon the bank, which vould ner ae ood foundation for 
; chimneys; but the distance a 9 the: heated. blast 
vo required to travel before reaching the twiers, would be 
an objection 
The hot-oven is built and arched over with brick, and strongly 
bound externally with iron, the heat being sufficient to destroy 
supports passing through it. It is sufficiently large to contain a 
small forest of upright flattened pipes about ten feet high, with 
an internal cavity of about four by seven or eight inches, the 
thickness of the metal being about an inch. These are main- 
tained at a red heat, the blast through them preventing their de- 
struction. They sti tand upon two large pipes or cylinders about 
a foot in diameter, and from twelve to fifteen feet 
long, with a single row of ape rtures, reais. 2 fig. 4,) 
and one or more (8, c) large enough to a 4 An 
double row of apertures. Over ] e neck of — 6 = 
aperture, a detached collar is placed, into which a [2 3 
pipe is firmly cemented, and the heads of two pipes |= 2 
on adjoining eylinders are similarly connected by an | 2 
auxiliary pipe. forming a semicircular or gothic arch, © et 
as represented in section in the upper part of the fig lo 2 
ure. The blast entering the first cylinder at a, meets [2/' 3 
a partition near the middle, and has to pass through le > 2 
the seven openings and pipes across the arched heads. e 2 
g 
into 6, and so on to d d, when it passes in the oppo 
site direction to its place, of exit at g, whence 
descends to the twiers. The partitions are not. i < middle of 
the cylinders, because by the time the air has passed | a through 
them, it requires more room on account of its expansio 
The operations and general results ane ital iron sii an- 
thracite, may be eel at a future 
«cg eo ' ° x a mf 4 
i 
. S 
tatp, tail cctisdan cht! copne, Puhd ehatioteien States ; m5 
Professor Kunzz of Leipzic, 1846-+-(Commu: municated by Dr. 
G. Eneeimann.) | inom unsaid 
7 tee ‘eee ne 
Tue plants of this Sotnily pects the sthemse of ocean-islands, 
more particularly within the tropics; the number of species is 
very limited on the large: continents, . especially in cold» or tem 
perate latitudes. We'observe the same fact in the United States; 
the ferns of which are not numerous, though it is supposed» that 
in the western and. southern parts of the union, several may yet 
be discovered. Several species new to the flora of the Baikal 
