x 522 
metronome with contact-pieces dipping into mercury-cups at 
each oscillatim, a condenser being placed under the instrument 
to get rid cf the extra current, and so to equalise the physio- 
logical effect of the making and breaking currents. 
‘The measurement of induced currents presented consi¢erable 
difficulties. The Conference at Paris had recommended the use 
of standard induction-cvils, bnt this method does not give any 
but arbitrary measures. Dr. Stone had tried and showed a 
vacuum-tube, in which the tension of air could be varied by c m- 
bining it with a barometric-column and a movable cistern. This 
gave aready means of varying the force af the discharge, by 
using it as a shunt of variable resistance, and had the interesting 
re-ults of shunting the ‘‘make-current” at a definite point, while 
allowing the ‘‘ break-current,” which is about six times stronger, 
to pas; between the platinum points; thus obtaining an induced 
current in one direction only. Latterly he had adopted also 
condensers of definite capacity charged to definite potentials. 
The writers were, howcver, still experimenting with another 
method, depending on Sir W. Thomson’s determinations of 
spark-length. The mo.t practical method, at present, seemed 
to be to pass a continu jus Current of measured st ength through 
an automatic commuta’or, which at alternate oscillations diverted 
it in one and the other direction, If there was any real physio- 
logical value in rapid reversals of direc ion, as was claimed by 
some experimenters, it could thus be secured, wihout the use of 
an induction coil. Another form of rotating-commutator was 
also shown, in which an ebonite cylinder, pressed on by six 
springs, at each qua-ter-tura connected, first, the condenser to 
the battery, so as t» charge it, and then di charged it through 
the patient. To obyate the necersity of employing a large 
battery with the condenser arrangemeu's, Planté’s secondary 
battery could be charged in parallel position from a small number 
of Groye’s cells, and discharged throuzh the condenser in series. 
In all these contrivances, however, as the current gained in 
tension, it seemed to lose somewhat in chemical and catalytic 
power, and to assimilate gradually to the static form. 
In the discussion which followed Mr. l’reece pointed out that 
the u e of electricity fur curative purposes had been advocated 
as long ago as the year 1759, by John Wesley, and recommended 
the use of the dynanometer for the measurement of induced 
currents, as this instru nent gave indications in the same direc- 
tion with all currents. Prof. McLeod, Mr. Fitzgerald, and 
Prof, Ayrton als» made comments on the pager. 
UNIVERSITY AND EDUCATIONAL 
INTELLIGENCE 
CAMBRIDGE.—It is proposed to spend 300/. extra within the 
next three years for the following objects at the Botanic Gardens: 
thinning the belt and yroups of trees; raising the level of some 
unoccupied areas and sowing them with grass; replanting the 
willow bed and making new beds ; and the improvement of the 
collection of trees, already good, so as to keep up its special 
reputation. 
Prof. Hughes having expressed to the Vice-Chancellor the 
serious difficul:y found in carrying on practical studies in the 
Woodwardian Museum without additional class-room accom- 
modation, it is arranged that Mr. Keeping, the curator, shall 
cease to reside in the museum, and be allowed an equivalent sum 
for hou-e-rent and other advantages attached to the curatorship, 
Prof. Humphry pro; 0-es to take classes in Surgery during the 
Long Vacation. 
SCIENTIFIC SERIALS 
Fournal of the Franklin Institute, January.—A new odonto- 
grapb, by 1. Bilgram.—Dimensions and performance of the 
hull and machinery of the U.S. steamer Despatch, by chief- 
engineer Isherwood.—Mechanical drawing, by C. Sellers, jan.— 
The application. of frictional electricity to the purification of 
widdlings, by RK, Grimshaw.—On the constants in Gordon’s 
formula for the strength of columns, by M. Merriman,— Chrono- 
logical table of American patents, by E. Hiltebrand. 
Annaten der Physik und Chemie, No. 2.—On the elliptical 
polarisation of light in reflection at crystal surfaces, by E. 
Schenek.—Influence of mechanical hardness on the magnetic 
properties of steel and iron, by L. M. Cheesman.—On the 
maximum of magnetisation of diamagnetic and weakly-paramag- 
netic bodies, by H. W. Eaton.—On the reflection of electric 
NATURE 
[ March 30, 1882 
rays ; the influence of the cathode’s form on the distribution of 
the phosphorescent light in Geis-ler-tubes; the connection 
between density of gas and layer-interval in Geissler-tubes ; and 
the ba d-spectrum of air, all by E. Goldstein.—On the forma- 
tion of peroxide of hydrogen during combustion, by A. Schudler. 
—Keply with regard to the formation-heat of water, by the 
same.— The expan-ion of water through absorption of gases, by 
K. Angstrém.—Theory of refraction on a geometrical basis, by 
A. Kerber.-—On the minimum of rotation of the light-ray in 
combined refraction and reflection at a sphere, by F. Kessler.— 
The minimum of deflection of a light-ray by a prim, aud the 
minimum of time in refraction of light, by the same.—On 
electric shadows, by P. Riess. 
Archives des Sciences Physigques et Naturelles, February 15.— 
A hypothesis on the origin of species, by M. Thury.—Deter- 
mination of the quantity of organic substances contained in 
waters of the Khéne, by MM. Graebe and Guye.— Dry plants 
found in mummies, by Dr. Schweinfurth.—Study on the 
chemical composition of albuminoid substances (continued), by 
a Danilewsky.—Swiss geological review for 1881, by M. 
avre, 
Journal ae Physique, February. —Thermodynamic acceleration 
of the earth’s motion of rotation, by Sir W, Thom:on,—I]mita- 
tion of the forces acting in a dielectric, by M. Elie.—Electric 
lighting, by M. Foussereau.—Projection of the focus of the 
prism, by M. Crova.—On a phenomenon of physiological optics, 
by MM. Macé de Lepinay and Nicati. 
Natura, February.—On the origin of metamera, by G. 
Cattaneo,—On the origin of electricity of thunder-clouds (con- 
tinued) by F, G, Nachs.—Some notes on radiophony, by E. 
Mirabelli. 
Riale Istituto Lombardo di Scienze e Lettere. Rendiconti, vol. xv. 
fasc, 1.—Aésumé of meteorological observati ms at Milan, in the 
Brera Ob:ervatory, by P. Frisiauii—On livear systems, by E. 
Bertini. ’ 
Fasc. 2.—New indicator, at a distance, of the temperature 
of an inclosure, by RK. Ferrinii—On two nummulitic deposits in 
the Pavian Apennines, by E. T. Taremellii—Phosphates and 
wheat, by G, Cantoni.—On the theory of the diatomic scale, by 
E. Beltiami.—The double quadratic transformation of space and 
its application to non-Euclidean geometry of space (continued), 
by C. F. Aschieri.—Kesults of observations during 1881 at the 
Brera Observatory, on the diurnal excursions of the magnetic 
needle, by E. G. Schiaparelli. 
SOCIETIES AND ACADEMIES 
LONDON 
Linnean Society, March 16.—Sir John Lubbock, Bart., 
M.P., F.R.S., president, in the chair.—Messrs. H. M. Brewer, 
V. I. Chamberlain, and A. P. Withiel Thomas were elected 
Fellows of the Society.—Mr. J. Worthington Smith called 
attention to certain very destructive Australian fungi new to 
England, viz. Cafnodium australe, fatal to conifers, especially 
Thuyas and Jsarta fuciformis, a great pest to grass in Kent and 
Sussex. The latter plant is popularly supposed to induce a 
disease similar to diphtheria, and said to be fatal to cattle. 
/saria frequently grows on animal substances, dead and living, 
as on larvee and pup of ichneumons, spiders, moths, wasps, &c.— 
Mr. Smith showed a bee caught alive in this country, and having 
a profuse growth of the /savva-condition of the Cordiceps spheco- 
cephala, a West Indian form, the latter genus being closely 
allied to C/avicefs, or Ergot.—Dr. Francis Day read a paper 
upon the Salmoues found in the British Isles, remarking how 
great changes are occasioned by retaining any of them in unsuit- 
able localities. He objected to the augmentation in number of 
the British forms of migratory trout, from three to seven, as 
made by Dr. Giinther, holding that we merely possess two, 
The Lochleven trour, which is in reality a marine form, accli- 
matized to fresh water, whereas the remainder are solely trout 
races of the common brook trout.—A most interesting fact was 
brought forward, viz. that Mr. Arthur, in New Zealand, having 
lately examined the trout which were introduced there in 1869 
from ova originally obtained from the Thames and the west 
of England, found great structural changes had taken place. 
The fish in que-tion, moreover, living in different streams in 
New Zealand had also assumed local peculiarities of size and 
change of form; and, doubtless due to increased food, the annua 
