: NovEMBER 19, 1903] 
*NMATLURE 
SR 
Travaux, 1839.—Prof. A. E. H. Love, The propagation of 
wave-motion in an isotropic elastic solid medium. The 
chief object of the paper is to remove a difficulty in Stokes’s 
memoir on the dynamical theory of diffraction. Stokes’s 
theory was built upon certain expressions for the cubical 
dilatation and the components of rotation, but these ex- 
pressions are not always correct. A new foundation is now 
obtained for the theory in an independent investigation of 
the effects produced by force applied at one point. A know- 
ledge of these effects renders possible the solution of a 
number of problems relating to wave-motion in an isotropic 
elastic solid, among them being the problem discussed by 
Stokes of the effects of arbitrary initial disturbances. It 
is proved that, unless certain relations connect the initial 
velocity and initial strain at points on the boundary of the 
portion of the medium which is disturbed initially, the strain 
in the neighbourhood of the centres of principal curvature 
of this surface will tend to become infinite, and fracture of 
the material will be produced.—Mr. H. Hilton, On spherical 
curves. The paper contains a general discussion of the 
curves on a sphere formed by the intersection of the sphere 
and any other algebraic surface.—Mr. W. H. Young, On 
sequences of sets of intervals containing a given set of 
points. A set of points being taken, intervals are con- 
structed so that each interval has one of the points as an 
internal point, and the lengths of the intervals are diminished 
without limit. The author discusses the nature of the 
aggregate of points which throughout the limiting process 
remain internal points of the intervals.—The Rev. F. H. 
Jackson, A formal generalisation of Maclaurin’s theorem. 
—Dr. H. F. Baker, On the Weddle quartic surface. Of 
the quadric surfaces which pass through six given points, 
those wiich pass through a seventh point pass also through 
an eighth; when these two coincide they must lie on a locus 
which is the surface under discussion. There is a birational 
relation between this surface and Kummer’s sixteen-nodal 
quartic, and this relation is interpreted as a linear projec- 
tion in space of four dimensions. From any point of 
Weddle’s surface there can be derived by linear projections 
in three dimensions a remarkable figure of 32 points lying 
on the surface, and the formula by which the coordinates 
of these points are connected with those of the first point 
constitute an Abelian gréup.—Mr. W. H. Jackson, The 
theory of diffraction.—Mr. G. H. Hardy, A general theorem 
concerning absolutely convergent series.—Prof. R. W. 
‘Genese, Notes on quaternions, including a geometrical in- 
terpretation of VaBy.—Mr. E. T. Whittaker, On the ex- 
pression of the electromagnetic field by means of two scalar 
potential functions. It is shown that the electric displace- 
ment and magnetic force due to any system of moving 
electrons can be expressed by second derivatives of two 
scalar potential functions—Mr. P. W. Wood, Analogue of 
the Jordan lemma for four variables. ~ 
Entomological Society, October 21.—Frof. E. B. Poulton, 
F.R.S., president, in the chair.—Mr. J. H. Keys sent for 
exhibition a black variety of Carabus nemeralis, Miill., 
from Dartmoor.—Mr. G. C. Champion exhibited a series 
of Rosalia alpina, Linn., found by himself on old beech 
trees at Moncayo, north Spain, in July last.—Mr. A. J. 
Chitty exhibited a larva of Dytiscus flavescens, taken at 
Eastling, Kent, near the school buildings.—Colonel J. W. 
Yerbury exhibited Gastrophilus nasalis, Linn., taken at 
Torcross, Devonshire, from August 19 to 31 last. He said 
that as this rare species differs in a marked degree in its 
mode of flight, &c., from the common horse bot-fly, Gastro- 
philus equi, it would be as well to direct attention to these 
differences." Gastrophilus equi, when flying round a horse, 
visits as a rule the bélly and the forelegs. The Q carries 
her ovipositor almost horizontal, and she looks, when on 
the wing, like the lower two-thirds of the letter Z (L), 
G. nasalis, on the other hand, carries the ovipositor tucked 
under the belly and almost parallel to the axis of the body ; 
this gives her, when on the wing, a peculiar ball-like 
appearance; G. nasalis, too, always flies to the horse’s 
head. As a rule, the horse paid no attention to G. equi, 
but G. nasalis caused him great alarm. The eggs of 
G. equi were in hundreds on the shoulders and forelegs of 
one cart-horse, but although the face and nostrils were 
‘searched carefully no signs of eggs or larve could be 
NO. 1777, VOL. 69] 
found thereon. Exhibiting Chersodromia hirta, Walk., he 
said ‘these little Empids were common on the shore near 
Prawle Point; some’ were obtained by sweeping over sea- 
weed, while others were running about over the sand. 
Colonel Yerbury also exhibited Pamponerus germanicus, 
Linn., from Barmouth and Porthcawl. He said this rare 
species appears to be struggling to keep its place in the 
British list. It appears to frequent the marram grass on 
the sand hills, and a Q taken at Barmouth on June 27 was 
preying on a beetle.—Mr. A. H. Jones, Mr. H. Rowland- 
Crown, Dr. T. A. Chapman, and Mr. R. W. Lloyd ex- 
hibited specimens of the genus Melitea from various 
European localities. A discussion on the probable affinities 
of the several named species which occur in the Alps took 
place.—The president also exhibited some forms of 
M. aurinia taken by Mr. A. H. Hamm at Basingstoke and 
elsewhere, and forms of M. athalia, M. didyma, and 
M. phoebe from Asia Minor and Persia.—Dr. T. A. 
Chapman exhibited an album showing a series of photo- 
graphs of the development of the embryo within the egg 
of Psammotis hyalinalis taken by Mr. W. H. Hammond 
and Mr. W. R. Jeffrey.—The president read, and com- 
mented upon, a paper received by him on protective color- 
ation in its relation to mimicry, common warning colour, 
and sexual selection, by Mr. Abbot H. Thayer. 
Zoological Society, November 3.—Dr. W. T. Blanford, 
F.R.S., vice-president, in the chair.—Dr. W. B. Benham 
communicated a memoir dealing with the aquatic Oligo- 
cheta of New Zealand.—Mr. Oldfield Thomas read a paper 
on the mammals collected at Chapada by Mr. A. Robert 
during the Percy Sladen Expedition to Central Brazil, and 
presented to the National Museum by Mrs. Percy Sladen. 
No modern specimens had hitherto been obtained from this 
little-known region. Thirty-seven species were enumerated, 
four of which were described as new.—Accounts were also 
given of the Coleoptera by Messrs. C. J. Gahan and G. J. 
Arrow, and of the Lepidoptera by Mr. F. A. Heron and 
Sir George Hampson, Bart., collected during the Percy 
Sladen Expedition. The former contained an enumeration 
of 175 species, of which fifteen were described as new, while 
the latter gave a list of nineteen species, one of which was 
described as new.—Prof. B. C. A. Windle and Mr. F. G. 
Parsons communicated a paper on the muscles of 
ungulates; in it the muscles of the hind limb and trunk 
were discussed.—Dr. P. Chalmers Mitchell read a note on 
the distribution of the cypriote spiny mouse. Specimens 
of this form, recently described as a new species (Acomys 
nesiotes) by Miss Bate, had been presented to the Gardens, 
and their localities showed that this mouse extended 
practically all over Cyprus.—Mr. F. E. Beddard, F.R.S., 
read a paper On some points in the anatomy, chiefly of the 
heart and vascular system, of the Japanese salamander 
(Megalobatrachus japonicus). 
Anthropological Institute, November 10.—Mr. H. Balfour, 
president, in the chair.—Dr. F. W. Edridge-Green ex- 
hibited a collection of pictures painted by colour-blind 
persons. Dr. Green divided the colour-blind into two 
distinct, independent, but associated classes. The first class 
consisted of persons with a spectrum shortened at one or 
both ends, who consequently cannot see certain rays. An 
individual with a shortening of the red end would not be 
able to see a red light at a distance, although he could 
pick out all the pieces in a bundle of coloured wools. The 
second class made mistakes through their inability to re- 
cognise the difference between certain colours. Normal 
sighted persons see six colours, some even seven; the second 
class of the colour-blind see five, four, three, two, or one 
colour, according to the degree of their defect, and are 
called pentachromic, tetrachromic, &c.—The president, on 
behalf of Mr. Annandale, read a paper on the survival of 
primitive implements in the Fzerdes and Iceland, and illus- 
trated the paper with an exhibition of many of the imple- 
ments alluded to. These included bone skates, a shovel 
made out of the bone of a whale, a stone lamp, and stone 
hammers. In the discussion which followed, the great im- 
portance of collecting these primitive implements -before 
they entirely vanish with the advance of civilisation was 
insisted upon. j 
