544. 
NATURE 
[ March 24, 1870 
mackerel-net off the coast of Cornwall, which he identified with 
Globiocephalus rissoanus—a species hitherto only known to occur 
in the Mediterranean. The specimen was stated to be an adult 
female, about eleven feet long.—Mr. Sclater gave some addi- 
tional details as to the correct locality of Amherst’s pheasant 
(Thaumalea Amherstic), in reference to Mr. Swinhoe’s commu- 
nication on the same subject at the previous meeting.—Prof. 
Owen read a memoir containing descriptions of various bones of 
Aftornis defossor, A. otidifornis, Notornis Mantelli and Dinornis 
curtus obtained from deposits in different parts of New Zealand, 
and forming the fifteenth part of his series of memoirs on the 
extinct birds of the genus Dizornis and their allies—Mr. R. 
Swinhoe read three papers on new or little known birds obtained 
by him in different parts of the Chinese Empire. The first of 
these related to new species obtained during a recent voyage up 
the Yangtze, amongst which were species of FParus, Lanius, 
Aégithalus, and other genera of Passeves. The second contained 
supplementary remarks on the pied wag-tails (J¥otaci//e) of 
China, in continuation of a former paper on the same subject. 
The third paper contained a notice of the different species of 
shore-plovers (#gza/ztis) found in China, amongst which was a 
conspicuous new species obtained on the Yangtze, and proposed 
to be called giahtis Hartingt.—Mr. 1. B. Sharpe read the 
second of a series of papers on the birds of Angola, containing 
an account of collections forwarded from that couutry by Mr. 
Monteiro. Amongst these was a bush-shrike belonging to the 
genus Lanzarius, supposed to be new, and proposed to be 
called Laniarius Monteirt.—Dr. Ginther read a note on the loca- 
lity of the Batrachian recently described by him as Megalixalus 
xobustus, which was stated to be from the Seychelles.—Dr. 
Giinther read a paper on the genus Profotroctes, which contains 
two species of fishes from the fresh waters of Southern Australia 
and New Zealand. In general appearance these fishesr esemble 
Coregonus, but their internal structure had led Dr. Giinther to 
constitute them along with the South American genus Haplochi- 
ton, a distinct family, MWaplochitonide, which appeared to be 
the representative of the Salmonoid group in the southern hemi- 
sphere. —A communication was read from the Rey. O. P. Cam- 
bridge, containing descriptions of three new species of the 
Arachnida of the genus /@zofs, in continuation of a former paper 
on the same subject. 
Mathematical Society, March 10. — Professor Cayley, 
president, in the chair. Mr. E. Bradshaw Smith was elected a 
member, and Messrs. A. and W. M. Ramsay were admitted 
into the society. Mr. Tucker (hon. sec.) then read two com- 
munications by Mr. Clerk Maxwell, F.R.S.; the one on topo- 
graphical geometry, which led to a discussion in which Mr. 
Archibald Smith, F.R.S., and the president took part; the 
other a note on a case of fluid motion. ‘*In most investigations 
of fluid motion we consider the velocity at any point of the fluid 
as defined in magnitude and direction: as a function of the co- 
ordinates of the point and of the time. We are supposed to be 
able to take a momentary glance at the system at any time, and 
to observe the velocities, but are not supposed able to keep our 
eye on a particular molecule during its motion. This method 
therefore properly belongs to the theory of a continuous fluid 
alike in all its parts, in which we measure the velocity by the 
volume which passes through unit of area rather than by the 
distance travelled by a molecule in unit of time. The molecular 
theory, as it supposes each molecule to preserve its identity, 
requires for its perfection a determination of the position of each 
molecule at any assigned time. As it is only in certain cases 
that our present mathematical resources can effect this, I propose 
to point out a very simple case with the results. Let a cylinder 
of infinite length and of radius @ move with its axis parallel to 
z, and always passing through the axis of x with a velocity v, 
uniform or variable in the direction of x through an infinite 
homogeneous incomprehensible perfect fluid.” The solution of 
the problem involved work hardly suited for the columns of 
Nature.—Mr. S. Roberts then discussed the following problem 
which occurred in his paper on the pedals of conic sections. If 
two circles are given, one of which passes through the centre of 
the other, and if a line equal in length to the radius of the latter 
circle moves with an extremity on each, the locus of any point 
rigidly connected with the moying line will be composed of a 
circle and a bicircular quartic having a finite double point. His 
account of the communication closed with a discussion of the 
following problem, intimately connected with the subject-matter 
of the paper :—Given the paths of two points of an indefinite 
plane, moying in plane space, to find the path of an arbitrary 
point of the plane. If A(x,v)=0, $(x,1)=0 are the equations 
of the given path, we have to eliminate @ from 
F (/cos@ + psin @ + X,/sin@ — Acos6+ Y) =o 
 (Zcos 8 — gsin@ + X,/sin@ + gcos@+ Y) =o 
The president, Professor Hirst, Mr. Cotterill, and the author, 
took part in a discussion on the paper.—Mr. Archibald Smith 
then made some remarks on the scale for compensation in the 
Irish Land Bill. 
MANCHESTER 
Philosophical Society, March 8.—Dr. J. P. Joule, presi- 
dent, in the chair, Sir James Cockle, President of the Queens- 
land Philosophical Society, was elected a corresponding member 
of the society. A letter was read from Mr. Dancer, on Dr. A. 
Ransome’s paper ‘* On the Organic Matter of Human Breath.” 
Mr. FE. W. Binney called the attention of the meeting to the fright- 
fully high death-rate of Manchester and Salford, which continued 
to increase, notwithstanding the appointment of officers of health, 
and the doings of the councils of the two towns. A paper was 
read, ‘On the Suspension of a Bail by a Jet of Water,” by 
Osborne Reynolds, Professor of Engineering, Owens College. 
Microscopical and Natural History Section, February 28.—A 
paper was read ‘‘On some Shell Deposits at Llandudno,” by 
Mr. Joseph Sidebotham. 
Physical and Mathematical Section, January 4.—Mr. E. W. 
Binney, president of the Section, in the chair. A paper was 
read ‘* On the Rainfall of 1869, at Old Trafford, Manchester,” 
by Mr. G. V. Vernon. 
March 1.—Mr. E. W. Binney, president of the Section, in the 
chair.—A paper was read ‘*On the Results of Rain-gauge and 
Anemometer Observations made at Eccles, near Manchester, 
during the year 1869,” by Mr. Thomas Mackereth. 
HEREFORD 
Woolhope Naturalists’ Field Club, February 22. — 
Annual meeting; Mr. James Rankin in the chair. After the 
usual club business had been transacted, and a committee ap- 
pointed to report upon the practicability of establishing a local 
museum, the Rev. F. T. Havergal detailed the progress that had 
been made with reference to the publication of the Mappa Mundt, 
one of the chief curiosities of the Cathedral. It has been satis- 
factorily established that the date at which the map was executed 
was the very commencement of the fourteenth century. It is 
drawn in accordance with the prevailing notions of geography at 
that period; the habitable earth is represented as a circular 
island with the ‘‘ocean-stream ” flowing around it. Jerusalem 
is placed in the centre. Asia occupies nearly the whole upper 
(or eastern) half of the circle, while Europe holds the lower 
quarter on the left hand, and Africa that on the right. The 
Hereford map is distinguished from most mediaeval maps not 
only by its great size, but also by its illustrations of objects in 
natural history, and its numerous inscriptions. It is proposed to 
publish a fac-simile (obtained by photography) in colours, accom- 
panied by an exhaustive account of the history of the map, and 
of the legends upon it. The price has been limited to two 
guineas, and Mr. Stanford, of 6, Charing Cross, London, has 
been empowered to receive orders.—A paper upon the Repro- 
ducton of the Mistletoe, by the Rey. R. Blight, was read, and 
drawings exhibited which showed the gradual penetration of the 
parasite through the bark of the Magnolia in search of the sap.— 
A new Clavis agaricinorum, by Mr. Worthington Smith, F.L.S., 
was also exhibited. Its principle of classification is based on 
the colour of the spores, and the book is divided into sections 
respectively coloured white, pink, brown, purple, and black. 
In each of these sections the typical forms of the different agarics 
are given, and the identification of any species is thus the work 
of a moment.—Dr. Bull communicated the discovery of an 
Agaric entirely new to Britain, the Cortinarius russus, which 
he had met with in several woods near Hereford. He had also 
collected specimens of the rare Asarum Europeum, or Asara- 
éacca, near the ruins of Limebrook Priory, a habitat which con- 
firms the belief in its having been a cultivated plant.—At the 
evening meeting the President reviewed in his address the pro- 
gress of science during the past year, and referred to the contri- 
butions made by different members of the club to various 
branches of natural history and archzeology.—Dr. Bull read an 
interesting paper upon Deerfold Forest which, when published, 
will form a very valuable addition to the topography of the 
county. —The Rey. H. Cooper Key was elected president for the 
ensuing year, 
4h 
