Fune 2, 1870] 
the palpus of one of the maxille. This furnishes an additional 
fact to Mr. Billings’s most interesting discovery, besides confirm- 
ing its correctness. Mr. Woodward considers the so-called 
‘*Panderian organs ” to be only the fulcral points upon which 
the pleurze move, and showed that such structures exist in most 
recent Crustacea. He considered that the evidence tended to 
place the Trilobita near to, if not in, the Isopoda Normalia, 
and remarked that the prominence of the hypostome reminded 
one strongly of that organ in Afzs, and suggested that we might 
fairly expect to find that the Trilobita presented a more genera- 
lised type of structure than their representatives at the pre- 
sent day, the modern Isopoda. 
*¢On the Structure and Affinities of Stei//aria, Calamites, and 
Calamodendron.” By J. W. Dawson, LL.D., F.R.S., F.G.S.; 
Principal and Vice-Chancellor of M‘Gill University, Montreal. 
The object of this paper was to illustrate the structure and affi- 
nities of the genera above named, more especially with reference 
to the author’s previous papers on the ‘‘Structures in Coal,” 
and the ‘‘ Conditions of Accumulation of Coal,” and to furnish 
new facts and conclusions as to the affinities of these plants. 
With reference to Sigi//aria, a remarkably perfect specimen of 
the axis of a plant of this genus, from the coal-field of Nova 
Scotia, was described as having a transversely laminated pith of 
the Sterndergia type, a cylinder of woody tissue, scalariform in- 
ternally, and reticulated or discigerous externally, the tissues much 
resembling those of Cycads. Medullary rays were apparéut in 
this cylinder ; and it was traversed by obliquely radiating bundles 
of scalariform vessels or fibres proceeding to the leaves. Other 
specimens were adduced to show that the species having this 
kind of axis had a thick outer bark of elongated or prosenchy- 
matous cells. The author stated that Prof. Williamson had 
enabled him to examine stems found in the Lancashire coal-field, 
of the type of Binney’s Sigt/laria vascularis, which differed in 
some important points of structure from his specimens; and that 
another specimen, externally marked like Sigi//aria, had been 
shown by Mr. Carruthers to be more akin to Lefidodendron in 
structure. These specimens, as well as the Sigi//aria elegans 
illustrated by Brongniart, probably represented other types of 
Sigillarioid trees, and it is not improbable that the genus Sig7/- 
laria, as usually understood, really includes several distinct 
generic forms. The author had recognised six generic forms in 
a previous paper, and in his ‘‘ Acadian Geology ;” but the type 
described in the present paper was that which appeared to pre- 
dominate in the fossil Sigillarian forests of Nova Scotia, and 
also in the mineral charcoal of the coal-beds. This was illus- 
trated by descriptions of structures occurring in erect and pros- 
trate Sigi//ari@, on the surlace of Sterndergia-casts, and in the 
coal itself. The erect Calamites of the coal formation of Nova 
Scotia illustrate in a remarkable manner the exterior surfacé of 
the stems of these plants, their foliage, their rhizomata, their 
roots, and their habit of growth. Their affinities were evidently 
with Zgwiselacee, as Brongniatt and others had maintained, and 
as Carruthers and Schimper had recently illustrated. The inter- 
nal structure of these plants, as shown by somé Specimens col- 
lected by Mr. Butterworth, of Manchester; and soon to be pub- 
lished by Prof. Williamson, showed that the stems were moré 
advanced in structure than those of modern Lgujiseta, and enabled 
the author to explain the various appearances presented by these 
plants, when the external surface is preserved, wholly or in part, 
and when a cast of the internal cavity alone remains. It was 
further shown that the leaves of the ordinary Calamites are linear, 
angular, and transversely wrinkled, and different from those of 
the As/erophyllites properly so called, though some species, as 
A. comosus, Lindley, are leaves of Calamites. The Ca/amodendra, 
as described by Cotta, Binney, and others, and further illustrated 
by specimens from Nova Scotia, and by sevéral interesting and 
undescribed forms in the collection of Prof. Williamson, are 
similar in general plan of structitre to the Calamités,; but much 
more woody plants ; and, if allied to Lywisetacee; ate greatly 
more adyanced in the structure of the stem than the modern 
representatives of that order. Specimens in the collection of 
Prof. Williamsen show forms intermediate between Calamites 
and Calamodendron, so that possibly both may be included in 
one family ; but much further information on this subject is re- 
quired. The tissues of the higher Ca/aimodendra ate similar to 
those of Gymnospermous plants. The wood or vascular matter 
of the thin-walled Calamites consists of multiporous cells or 
yessels, in such species as have been examined. In conelusion, 
a table was exhibited showing the affinities of Sigiligrig on the 
one hand, through Clathraria and Syringodendran with Ly copo- 
NATURE 
95 
diace@ ; and on the other hand, through Ca/amodendron with 
Equisetacee ; while in the other direction they presented links 
of connection with Cycads and Conifers. 
“‘Notes on the Géology of Arisaig, Nova Scotia.” By the 
Rey. D. Honeyman, D.C.L.; F.G.S. The author referred to a 
previous paper on the Upper Silurian Rocks of Nova Scotia, 
which he stated appeared to him now to be generally repetitions 
of his Arisaig seriés. He noticed the occurrence of fossils in one 
of the beds previously supposed to be almost destitute of or- 
ganic remains, and described the occurrence, in Arisaig town- 
ship, of a band of crystalline rocks which appeared to contain 
Lozoon, and were probably of Laurentian age. A note from 
Prof. Rupert Jones, giving an account of the fossils referred to by 
Dr. Honeyman, was also read. 
Chemical Society, May 19.—Warren De la Rue, F.R.S., 
vice-president, in the chair. Mr. S. H. Johnson was elected 
a fellow. Mr. Griffin. exhibited and explained a new gas 
furnace which is capable of melting about three pounds of 
iron in little more than one hour.—Mr. Walern described an 
advantageous method for coating cast-iron objects by electro- 
lysis with copper or brass. The special peculiarity of the method 
consists in the circumstance that no hydrogen is evolved during 
the process. A calico printing valse and other articles, coated 
with brass, in this manner, were submitted to the inspection of the 
assembly.—Mr. Tookey, Assayerin the Japanese Imperial Mint, 
communicated a paper “ On the Manipulations of Assays of Gold 
and Silver Bullion.’? The number of separate processes from the 
first weighing in of a piece of gold bullion to the second weigh- 
ing out before its value can be ascertained are well known to all 
assayers, The author saves a good deal of time by proceeding 
in the following manner :—The bullions are placed in conical 
shaped platinum tubes, which, at their narrow ends, are closed 
witha perforated plate, and at the wider end are provided with 
a shoulder, so that they can be supported by a porcelain tile 
having circular holes. The tubes and holes are numbered. 
The entire arrangement is then immersed in hydric nitrate, &e. 5 
in short, proceeded with as if a single bullion, instead of a 
batch of them had to be treated. With regard to the assay of 
silver bullion, the hammering and brushing of the buttons after 
they have been detached from the cupels, may be dispensed 
with by placing those buttons into the perforated cavities of a 
platinum plate, where they are fastened by a platinum wire, and 
immersing the plate in pure hydric chloride, which will dissolve 
all the bone ash adhering to the buttons. Thé cavities of the 
plate are numberéd to correspond with the cupels in the muffle. 
—Mr. Perkin read 4 note ‘‘On some Broimine derivatives of 
Coumarin.” The following definite compounds have been ob- 
tained by treating coumarin with bromine in different ways : 
dibromide of coumarin, Cy H O, Br, ; bromo-coumarin, CgH, 
BrO,, and dibromo-coumarin, CgH,Br,O,. All the three com- 
pounds are easily soluble in hot alcohol, from which they crystal- 
lise out on cooling. Dibromide of coumarin fires at about 100°, 
bromo-coumarin at 110°, dibromo-coumarin at 174°. The two 
latter compounds form, when boiled with an aqueous solution 
of potassic hydrate, potassium salts of new acids, probably 
bromo, and dibromo-coumaric acids—Dr. Divers made some 
remarks “On the precipitation of solutions of ammonic 
earbonaté, sodic carbonate; and ammonic carbonate by calcic 
chloride.” The results of these experiments are chiefly 
of interest as supplying a characteristic reaction for the 
carbonate. When ammonic carbonate is added in excess to an 
aqueous solution of ammonia and calcic chloride, the calcic car- 
bonate is precipitated very slowly in the cold, whilst such pre- 
cipitate is instantly produced when ammonic carbonate is added 
to a solution of caustic ammonia and calcic chloride in water.— 
Dr. Thudichum made a short communication about having 
obtained hydric acetate from fresh urine, which fact contradicts 
the statements of Berzelius, Lehmann, and Liebig. 
EDINBURGH 
Institution of Engineérs, April 19.—Professor Macquorn 
Rankine, C.E., LL.D., president, in the chair.—‘ On thé Patent 
Law.” By Mr. R. S. Newall. After some general remarks 
Mr. Newall proceeded as follows :—In brief, then, my propo- 
sitions are:—The appointment of a standing commission 
who shall examine, in public, all petitions and specifications, 
&c., before the granting of a patent. ‘That when once a patent 
is granted, it shall be held as valid, if not assailed within two 
years, under certain eonditions. I do not seé why thé inventor’s 
letters patent should ng{ be made as secure and held as sacred 
