408 On Spirally dotted Ducts in Anthracite Coal. 
tially burned Pennsylvania anthracite, with which a grate in my 
room was filled, in which the fire had been allowed to smother 
itself in its own ashes. 
I was not disappointed, for I found that many of the masses 
of partly burned coal readily separated into numerous lamine, on 
almost all of which, when magnified, vegetable structure could 
be detected, and on many of which the tissues were preserved 
in a state of unhoped for perfection. 
Several varieties of structure presented themselves, the most 
interesting of which however were well characterized dotted or 
sealariform ducts, in a most perfect state of preservation, and 
forming somewhat rectangular plates, which are often several 
inches long, and one or more broad. ‘These specimens, whose 
beauty and perfection can scarcely be exaggerated, present all the 
original markings of the vessels with a distinctness which leaves 
scarcely any thing to be wished for. They may be examined 
either as opaque objects, in which case the silica appears in relief 
against the black coal, and shows the form and markings of the 
tubes very finely; or still more satisfactory results may be ob- 
tained by melting some inspissated Canada balsam upon a plate 
of glass, and while melted touching it to a surface of the coal upon 
which the ducts had been previously found to exist. When the 
balsam has hardened, the coal may be pulled off, and it will be 
found that it leaves fixed upon the balsam a thin layer of silica, 
containing perfectly preserved dotted vessels, which when viewed 
as transparent objects, are nearly as distinct in their markings as 
if freshly obtained from a recent plant. (See the figures, p. 410.) 
I have a large number of specimens, and hope to find means to 
place them in the hands of all interested in such researches. 
Besides the dotted vessels, which appear to be something very 
different from the “ prosenchymatous cells of wood” obtained by 
Schultz, other tissues occurred, among which were small masses 
of woody fibre with no definite markings, also layers appearing 
to be composed of the cells of the epidermis of the stem of some 
plant, and, rarely, traces of tissue presenting what appear to be 
the remains of Stomate. All these require a more careful study 
before any very definite conclusion can be drawn from them. 
A few inferences appear however to be fairly deducible from 
the examination already made, viz. 
1. It appears that almost every layer of the coal is composed 
of vegetable matter, which still retains very distinct remains of 
