Nov. 24, 1881] 
structive to ostrich chicks at Grahamstown and elsewhere in | 
‘South Africa, The worm somewhat resembles certain free 
nematodes, and bears few eggs. 
Mathematical Society, November 10.—S. Roberts, F.R.S., 
president, in the chair.—At this, the annual meeting, the trea- 
surer read his report, from which it appeared that the Society 
‘was ina very flourishing condition. The following gentlemen 
were elected on the council of the present session :—President— 
'S. Roberts, F.R.S. Vice-presidents—Dr, Hirst, F.R.S., and J. 
W.L. Glaisher, F.R.S, Treasurer—C. W. Merrifield, F.R.S. 
Hon. Secretaries—Messrs. M. Jenkins and R. Tucker. Other 
members—Prof. Cayley, F.R.S., Sir J. Cockle, F.R.4., H. 
Hart, Prof. Henrici, F.R.S., A. B. Kempe, F.R.S., Prof, 
Rowe, R. F. Scott, Prof. H. Smith, F.R.S., H. W. Lloyd 
‘Tanner, and J. J. Walker. Mr. W. W. R. Ball, Fellow of 
Trinity College, Cambridge, and the Rey. G. Pirie, Professor 
of Mathematics in the University of Aberdeen, were elected 
Members of the Society. The following communications were 
made :—Note on the limit to the number of different proper 
fractions whose denominators are less than x, where x is large, 
by Messrs. Jenkins and Merrifield, ’.R.S.—On the oscillations 
of a viscous spheroid, by Prof. H. Lamb, Adelaide.—A geo- 
metrical representation of a system of two binary cubics and their 
associated forms, by W. R. W. Roberts.—On the infinitesimal 
bending of surfaces of revolution, by Lord Rayleigh, F.R.S.— 
On tangents to a cubic forming a pencil in involution, by R. A. 
Roberts.—Note on Landen’s theorem, by Prof. Cayley, F.R.S. 
Chemical Society, November 17.—Dr. Gilbert, F.R.S., in 
the chair.—It was announced that a ballot for the election of 
Fellows would take place at the next meeting, December 1.— 
The following papers were read :—Aluminium alcohols, Part II. 
NATURE 
Their products of decomposition by heat, by J. H. Gladstone | 
and A, Tribe. The authors have studied the bodies formed when 
aluminic ethylate, aluminic phenylate, aluminic paracresylate, 
aluminic thymolate, aluminium, a naphthylate, and aluminium 
Bnaphthylate are decomposed by heat. The CnH2n+1 series 
yields the corresponding ethers, alcohols, and olefines, the 
CnH2n-7 series yields the corresponding ethers and alcohols, 
together with some new crystalline bodies which are probably 
ketones.—On the chemical action of decomposing vegetable 
matter on the rock-forming sediment of the Carboniferous 
period, by E. Wethered. The author points out that the 
rocks immediately overlying the coal are in nearly all cases 
argillaceous, and that in the few cases where arenaceous rocks 
occupy that position they have a well-marked tendency to be- 
come more argillaceous as they come into contact with the coal. | 
He proves by analysis that the chief difference in chemical | 
composition between the two rocks is that the argillaceous 
rocks contain much more alumina, and concludes that this 
difference in chemical composition is due to the carbonic acid 
evolyed by the decaying vegetation, decomposing all the silicates 
but that of alumina.—On a and 8 amylam, by C. O’Sullivan. 
The author has exhausted various grains, barley, wheat, rye, 
&c., with alcohol. The residue was then treated for some time 
with water at 40°, and the process repeated until nothing further 
was dissolved. The solution was filtered, evaporated, and 
precipitated with alcohol. The precipitate consisted of a and 
Bamylam. These bodies were very carefully purified ; the latter 
is soluble in cold, the first only in hot water. They have the 
composition of starch, but furnish apparently dextrose at once | 
when treated with acid, without the previous formation of 
dextrin or any other substance. Their optical and chemical 
properties are fully given in the paper.—On the action of oxides 
on salts, Part IV. Potassic chlorate and ferric oxide, by E. J. 
Mills and G, Donald. The authors conclude that the action of 
ferric oxide on potassic chlorate resembles its action on potas-ic 
carbonate to a certain extent, that the chemical change has 
nothing abnormal or peculiar in its features, and that the name 
catalysis ceases to have any reason for its existence.—On the 
steeping of barley, by E. J. Mills and J. Pettigrew. The 
authors have compared the effects produced by steeping barley 
in water, and in water containing gypsum and calcium carbonate, 
The general effect of a calcium solution is to retain the nitro- 
genous matter in the grain, but to increase the total amount of 
extract. They attribute the value of the Burton water to the 
nitrates which it contains, and the consequent stimulating effects 
it produces in germination. 
Zoological Society, November 15.—Prof. W. H. Flower, 
| (Zrogonide), 
F,R.S., president, in the chair.—Prof. Newton, I'.R.S., exhi- | 
95 
bited a specimen of Lmberiza rustica recently shot on the coast 
of Yorkshire.—The Rey. Canon Tristram exhibited and made 
remarks upon skins of a darter and a pigmy cormorant procured 
in June of this year on the Lake of Antioch.—Mr. Sclater exhi- 
bited a specimen of the glossy ibis (P/egadis Selcinellus) belonging 
to Sir Henry Mildmay, Bart., which had been shot in Hampshire 
in September last.—A communication was read from MM, L, 
Taczanowski et J. Stolzmann on the habits and various plumages 
of the rare humming-bird, Loddigesia mirabilis,—Communica- 
tions were read from M. L. Taczanowski, C.M.Z.S., on two 
nearly allied species of humming-birds of the genus Steganura 
from Peru, and on a new species of Austela from North-eastern 
Peru, which he proposed to call Mustela Stolamanni.—Mr. W. 
A. Forbes read notes on the structure of the palate in the trogons 
and on the systematic position of Hupetes macro- 
cercus.—A communication was read from Mr. E. P. Ramsay, 
C.M.Z.S., containing an account of the true habitat of Pycnoptilus 
Jloccosus, Gould.—A communication was read from Mr. E, L, 
Layard, F.Z.S., containing a note on the South African mollusk, 
Celiaxis Layardi, of Angas.x—A communication was read from 
Mr. Edgar A. Smith, F.Z.S., containing notes on the shells of 
the genus C/zlina, with a list of the known species. —Mr. Arthur 
G. Butler, F.Z.S., read a paper on some butterflies from Japan, 
with which were incorporated notes and descriptions of new 
species by Montague Fenton.—Mr. H. J. Elwes, F.Z.S , read a 
paper on the butterflies of Amoorland, Japan, and Northern 
China. 
Physical Society, November 12,—Prof. Fuller, vice-presi- 
dent, in the chair.—Mr, W. D, Niven was elected a Member.— 
Mr. Lewis Wright then read a paper on some spirals observed 
in crystals, illustrating the relation of their optic axes. After 
remarking that the relation of the axes in uni-ax’al and bi-axial 
crystals had always been an interesting subject, he observed that 
if we took any uni-axial and a single axis of any bi-axial which 
had little or no axial dispersion, and polarised and analysed each 
circularly, we ultimately got similar phenomena. This is illus- 
trated by calcite and a single axis of sugar, each giving, when 
thus treated, unbroken circular rings. From this it might be 
hastily inferred that a single axis of a bi-axial resembled in 
character the axis of a uni-axial, but this was not the view of 
those who framed the theory of double refraction in crystals, 
Fresnel finally framed the conception of three elasticities in 
three rectangular directions. If all were equal, there was 
no double refraction ; if only two were equal, there was a 
single optic axis in the direction of the third ; and if all were 
unequal, there were two optic axes. According to this theory 
the axis of the calcite did 7o¢ resemble in character a single axis 
of the sugar or other bi-axial, but was a limiting case in which 
both such axes coincided. This was illustrated by the beautiful 
experiment of Prof, Mitscherlich applying heat to a crystal of 
selenite, and thereby altering the respective elasticities. The two 
axes gradually approached until they coincided and the crystal 
became uni-axial, after which, on heating the crystal still more, 
the axes re-opened in a direction at right angles to the former, 
thus proving Fresnel’s theory. A point still to be illustrated 
was that the axis of a uniaxial did retain, or still embraced 
within itself in some visible form, characteristics of the two axes 
thus brought into coincidence. Sir George Airy had discovered 
the double spiral in quartz. Uniaxial calcite showed a double 
spiral ; and biaxials gave a single spiral. Mr. Wright repeated 
Prof. Mitscherlich’s experiment, with Airy’s additional method of 
analysis; the spirals being first shown perpendicularly arranged 
above each other. Gradually they approached until they resembled 
those of the calcite, and finally opened out again horizontally. All 
through there was a double spiral, and a single one could only 
be got by separating a single axis. The axis of a uniaxial 
always preserved what might be called its ‘‘twin” or ‘‘double” 
character. This experiment was the ocular demonstration 
sought that the axis of a uniaxial, as a limiting case, did contain 
or retain elements capable of being made visible. It further 
showed the reason of the double spiral discovered by Sir George 
Airy in quartz. This crystal evidently was able to show its own 
spirals, which, of course, are double. It was shown that as the 
convergence of the rings was increased these spirals became as 
numerous and definite as in the calcite. There was however a 
crucial test of this view : for if it were correct we could combine 
the two properties of the quartz, artificially as it were, since 
many fluids also possess rotary power. If therefore we took 
a column of such fluid of sufficient length and an ordinary 
uniaxial crystal, the fluid would represent the axial proper- 
