August 26, 1886] 
NATURE 
403 
and L. Arons, conductivity and dielectric constants. An in- 
vestigation as to whether the dielectric constant of a conductor 
is infinite, as often stated in text-books. A condenser was 
arranged to be filled with mixtures of anilin and benzol, xylol, 
mixtures of anilin and xylol in various proportions, &c., liquids 
being selected to avoid as far as possible residual charges. The 
capacities of this condenser were compared with that of an air- 
condenser, and arrangements were also made to measure the 
resistances on the bridge. The resistances of the three mixtures 
of anilin and xylol were 224,900, 1,383,000, and 18,780,000 
Siemens’s units, and their dielectric constants 1°590, 17443, and 
1°336. The authors conclude from these and other experiments 
that there is no necessary relation between the two constants ; 
and, further, that the wide differences observed by Hopkinson 
between the square root of the dielectric constant and the index 
of refraction in certain vegetable oils cannot be explained by 
the conductivity.—E. Hoppe, on the theory of unipolar induc- 
tion: experimental verification of Edlund’s theory of the origin 
in terrestrial magnetism of auroral phenomena.—H. Jahn, on 
the equivalence of chemical energy and current energy. A dis- 
cussion of Helmholtz’s theory of the secondary heat of a voltaic 
element.—H. Jahn, on galvanic polarisation. A study of 
changes of polarisation of certain liquids with changes of tem- 
perature, together with deductions verifying Helmholtz’s equa- 
tions.—G. Adler, on the energy of magnetically polarised 
bodies. —E. Ketteler, addendum on the total reflection of crys- 
tals. —F. Kolatek, on the gold-leaf spectroscope. An attempt 
to calculate a calibration of the electroscope from its electro- 
static capacity. 
THE number of the Muovoe Grornale Botanico Italiano for 
April 1886 contains a number of short articles on various points 
relating to the flora of different parts of Italy, both phanero- 
gamic and cryptogamic.—Sig. A. Mori describes and figures a 
singular instance of the production of a pitcher-like structure 
on the upper surface of a leaf of Gunnera scabra.—Dr. O. 
Mattirolo has examined the ‘‘mycorhiza” of the roots of the 
| sweet chestnut, and finds it to furnish a new example of poly- 
| morphism amongthe Hypocreacez. It consists largely of two 
species of fungus, which he names AZelanospora stysanophora 
| and 2%. Gibelliana. The former is identical with Stysanus 
| Steminotis and also with an Ac/adium, and presents an instance 
' of ‘‘apandry,” or the production of ascospores independently of 
the previous formation of a male organ. AZ. Gidelliana produces 
chlamydospores, and also the peculiar structures known as 
*€spore-bulbils,” which appear to replace the true ascophorous 
perithecia. 
The most interesting article in the number for July is by Sig. 
A. Piccone, on the plants growing wild in Liguria which he 
terms ‘‘zoophilous” or “‘ornithophilous,” ze. those which are 
absolutely dependent for the germination of their seeds on the 
fruit being swallowed by birds. 
SOCIETIES AND ACADEMIES 
LoNDON 
Entomological Society, August 4.—Prof. J. O. West- 
wood, M.A., F.L.S., in the chair.—The following gentlemen 
were elected Fellows :—Lord Dormer, Messrs. J. H. A. Jenner, 
| James Edwards, Morris Young, F. V. Theobald, “eG AS 
Atmore, and William Saunders, President of the Entomological 
Society of Ontario.—Mr, Theodore Wood exhibited and made 
remarks on the following Coleoptera: an abnormal specimen 
of Apion pallipes; a series of Langeandia anophthalmi, from 
St. Peter’s, Kent, taken in decaying seed-potatoes ; a series of 
Adelops wollastont, and Anommatus %12-striatus, also from 
decaying seed-potatoes; anda series of Baryfeithes pellucidus, 
from the sea-shore near Margate. Mr. Wood also exhibited, 
on behalf of Dr. Ellis, of Liverpool, a specimen of Apion 
annuliper.—Prof. Westwood exhibited five specimens of a 
species of Cwlex, supposed to be either C. cantans or C. lateralis, 
sent to him by Mr. Douglas, who had received them from the 
Kent Water-Works. It was stated that they were very 
numerous in July last, and that persons bitten by them had 
suffered from ‘‘ terrible swellings.” Prof. Westwood also exhi- 
bited some galls found inside an acorn at Cannes in January last.— 
Mr. Billups exhibited a male and female of Clefves nitidula, 
taken 27 cofu/d in July last, at Benfleet, Essex, on the flowers of 
Fleracleum sphondylium. We stated that it was probably the 
rarest of the twenty-two known species of British Chrysidide, 
though it had been recorded from the New Forest and from 
Suffolk. —The Rev. W. W. Fowler announced that a series of 
specimens of Homalium rugulipenne had been received from Dr. 
Ellis, of Liverpool, for distribution amongst Members of the 
Society.—Mr. White exhibited a group of three specimens of 
Lucanus cervus, consisting of a female and two males. The 
female was 7 copula with one of the males, which, while so 
engaged, was attacked by the second male.—Mr. E. A. Fitch 
read a paper, communicated by Mr. G. Bowdler Buckton, on the 
occurrence in Britain of some undescribed Aphides.—Prof. 
Westwood read a paper on a tube-making homopterous insect 
from Ceylon.—Mr. Theodore Wood read a paper on Bruchus- 
infested beans. A discussion ensued, in which Prof. West- 
wood, the Rev. W. W. Fowler, and Messrs. Weir, Fitch, and 
Trimen took part. 
PARIS 
Academy of Sciences, August 16.—M. Fizeau in the 
chair.—The Secretary announced the loss sustained by the 
Academy in the death of M. Laguerre, Member of the Section 
for Geometry, who died on August 13 at Bar-le-Duc. At the 
obsequies, which took place on August 16, the Academy was 
represented by M. Halphen.—Remarks on the recent volcanic 
disturbances in the Northern Island, New Zealand, by M. 
Emile Blanchard. The author pointed out that this sudden 
display of igneous activity was a remarkable confirmation of the 
views already advocated by him in 1882 and 1884 on the sub- 
sidence of an austral continent during the modern geological 
age of the earth. He regarded the New Zealand Archipelago 
and more or less adjacent islands as a remnant of this continent, 
or at least of an extensive region, which had existed in a com- 
paratively recent epoch, and he had already, in 1884, anticipated 
fresh convulsions, such as the tremendous catastrophe of which 
New Zealand had been the scene after a lengthened period of 
quiescence. Tarawera and other volcanoes supposed to be 
extinct have suddenly broken out into fresh activity ; lava- 
streams have overspread vast spaces, and a romantic tract of 
country, the delight of the early explorers, has been wasted 
or swallowed up. Although the exact change that has taken 
place in the aspect of the land cannot be fully known for some 
time to come, the event already appears as an illustration of 
still more violent outbursts, which occurred in more or less 
remote ages. Thus it has been shown in this instance that the 
inductions drawn from a recently-created science already bear 
the character of certainty.—On the differential equation of a 
curve of any order, by Prof. Sylvester. It isshown that a direct 
and universal solution may be had of the following problem : 
To find the differential equation of a curve of the order 2, where 
the function of the equation (with unity for constant term), 
whether U or (x, y, 1)” is represented under the symbolic 
form u”, where ~=a + $x+ 4. It is added that the 
formulas given by M. Halphen in his ‘‘ Recherches des points 
d’une courbe algébrique plane,” &c., lead to the same results 
as those here arrived at.—On the employment of inter- 
mittent light for the measurement of rapid movements, by M. 
Gustave Hermite. Indicators of velocity at present in use 
always absorb a portion of the force of the machine to which 
they are applied. The author proposes to avoid this inconveni- 
ence by the arrangement here described, which, by an ingenious. 
application of intermittent light, enables the observer to measure 
not only the number of revolutions of any machine, but the 
velocity of any rapid movement whatsoever, without exercising 
any mechanical action on the apparatus under examination. —On 
the mono-substituted haloid derivatives of acetonitril, by M. 
Louis Henry. The researches undertaken by the author on 
the functional solidarity and the volatility of the carbon com- 
pounds have led him to complete the series of these derivatives. 
Tlere he describes mono-ioduretted acetonitril, ICH,—CN, and 
monobromuretted acetonitril, BrCH,—CN, reserving for a 
future communication the comparative study of the mono-substi- 
tuted haloid derivatives of acetonitril and acetate of methyl.— 
On the composition of the mineral waters of Bagneres-de 
Luchon, Haute-Garonne, by M. Ed. Willm. It is shown that 
carbonic acid, far from being a negligible quantity in these and 
similar waters, as was supposed by the late M. Filhol, mostly 
occurs in a proportion more than sufficient to give a quantity of 
bicarbonates corresponding to the alkaline property of the water, 
independently of that which is due to the sulphuret. A com- 
plete analysis yielded sulphuric and carbonic acid, chlorine, 
