ApRIL 14, 1904 | 
NAT ORE 
575 
»Royal Microscopical Society, March 16.—Dr. D. H. 
Scott, F.R.S., president, in the chair.—Prof. A. E. Wright 
communicated the purport of his paper on some new methods 
of measuring the magnifying power of the microscope and 
of lenses generally. His remarks included the description 
of a piece of apparatus which he had invented for taking 
the magnifying power of the microscope and for the rapid 
measurement of microscopic objects. The instrument is 
placed over the eye-piece without disturbing any of the 
adjustments of the instrument, and the object on the stage 
can be instantaneously measured.—A short note by Mr. 
E. B. Stringer on the separation of ultra-violet light was 
read by the secretary.—Mr. Abraham Flatters exhibited on 
the screen a series of sixty hand painted lantern slides illus- 
trating botanical histology. 
Mineralogical Society, March 22.—Prof. H. A. Miers, 
F.R.S., vice-president, in the chair.—Irregularly developed 
crystals of zircon (specific gravity 40) from Ceylon: L. J. 
Spencer. The crystals were sent recently by Mr. A. K. 
Coomaraswamy to the British Museum for determination, 
and at first were thought to be rutile. They are of a 
dark brown colour and almost opaque; the specific gravity 
is 4-09, and is unaltered by heating. A section cut perpen- 
dicular to the principal axis shows interesting variations 
in the optical characters, successive portions being isotropic, 
uniaxial and biaxial; the mean refractive index is about 
20. After being heated to redness and cooled, the material 
is bright green in colour, and a crystal section is now 
entirely biaxial, although the interference figures and bire- 
fringence vary in different parts.—Notes on ** feather-ore ”’ : 
identity of ‘‘ domingite ’’ (=‘* warrenite ’’) with jamesonite : 
L. J. Spencer. ‘ Feather-ore’’ is usually considered to 
be a variety of jamesonite, but since the latter has a good 
cleavage perpendicular to the length of the fibres, only 
brittle “‘ feather-ore ’’ can be included in this species; on 
the other hand, ‘“‘ feather-ore,’’ the fibres of which are 
flexible, may be either stibnite, zinckenite, plumosite 
(2PbS.Sb,S,), boulangerite, or meneghinite. ‘‘ Warrenite ”’ 
is a brittle ‘* feather-ore,’’ and further has the same chemical 
formula (3PbS.2Sb,S,) as that originally given for the 
cleavable Cornish jamesonite.—Note on the indices of re- 
fraction of antimonite: A. Hutchinson. A prism, of 
refracting angle 8° 51’, was found sufficiently transparent 
to red light for the refractive indices to be determined in 
the usual way. The results obtained are 4-129 and 3-873 
for rays vibrating parallel to the axes of Z and X re- 
spectively. Measurements of the deviation of the ultra-red 
rays indicate high dispersion in this region of the spectrum. 
The investigation is being continued.—The connection 
between the atom arrangements of the crystals of certain 
allied carbon compounds: W. Barlow. Using balls of the 
same relative size as were employed in his previous work, for 
instance, in models of calcite, the author forms a carboxyl 
slab. By uniting such slabs with balls representing 
barium, a structure is obtained which has the symmetry of 
barium formate. Again, by uniting the slabs with balls 
representing hydrogen, a structure with the symmetry of 
oxalic acid is formed. The author showed that in certain 
cases, in order to effect close packing, a relative shift was 
necessary between successive layers. He also briefly dis- 
cussed the tartaric acids.—On the construction and use of 
the moriogram: G. F. Herbert Smith. The moriogram is 
a diagram devised by the author for the graphical determin- 
ation of the angles between tautozonal poles, obeying the 
law of rational indices.—Note relative to the history of the 
Caperr meteorite: L. Fletcher, F.R.S.—On the meteoric 
irons of Bethany, Lion River, Springbok River and Great 
Fish River, South Africa: L. Fletcher, F.R.S.—Prof. 
J. W. Judd, F.R.S., exhibited two Gardette twins of quartz. 
Geological Society, March 23.—Dr. J. E. Marr, F.R.S., 
president, in the chair.—On the Moine gneisses of the East- 
Central Highlands and their position in the Highland 
sequence: G. Barrow. Communicated by permission of 
the director of H.M. Geological Survey. The paper is 
divided into two parts. The first deals with the parallel- 
banded grey gneisses or gneissose flagstones of the Perth- 
shire and Aberdeenshire districts, which, in their field 
characters as well as in their composition and structure, are 
identical with the Moine gneisses of the North-West High- 
lands. A description is given of these gneisses, as seen in 
NO. 1798, VOL. 69] 
and about the Garry in Perthshire, and this is followed by 
a brief account of the same rocks in the ground to the 
east and north-east, extending to the Forest of Invercauld, 
north of Braemar in Aberdeenshire. Special attention is 
directed to the fact that towards the eastern end of the 
area large masses of highly quartzose gneiss occur, which 
are really part of the Central-Highland quartzites in what 
the author conveniently describes as a ‘‘ Moine-phase,’” and 
should not strictly be included in the typical banded grey 
gneisses at all. In the second part, dealing with the mode 
of ending off of these gneisses to the south-east, it is shown 
that they cease to be recognisable as Moine gneisses, owing 
to the fact that they thin away and also become more finely 
banded, while at the same time they become less crystalline 
or cease to be gneisses. To prove this, an account is given 
of a series of sections lying along a belt 4o miles in length, 
extending nearly from Blair Athole to the east of Balmoral, 
in Aberdeenshire. 
Royal Astronomical Society, April 8.—Prof. H. H. 
Turner, F.R.S., president, in the chair.—The secretary read 
a paper by Mr. H. C. Plummer on the optical distortion 
of the microscopes of the Oxford machine for measuring 
astronomical photographs. Dr. Russell and Mr. Hinks ex- 
plained the form of the microscope. of the Cambridge 
measuring machine, and the Astronomer Royal described 
that which was employed .at the Royal Observatory, 
Greenwich.—Mr. F. A. Bellamy read a paper, being an 
analysis of the results of measurements of the 1180 plates 
in zones +25° to +31°, allotted to the University Observ- 
atory, Oxford, in connection with the International Astro- 
graphic Chart.—Mr. Thomas Lewis gave an account of 
his memoir, measures of the double stars in Struve’s 
““ Mensurz Micrometrice,’’ collected and discussed.—Prof. 
Turner read a paper on the Rousdon variable star observ- 
ations. In the course of the paper was a consideration of 
the sun as a variable star. The evidence appeared in favour 
of the sun being brighter at periods of maximum activity 
of sun-spots than at minimum.—Sir David Gill spoke upon 
recent work at the Royal Observatory, Cape of Good Hope. 
He gave an account of an improved spectroscope which the 
observatory owed to the generosity of Mr. McClean, illus- 
trated by photographs of the instrument and its accessories. 
He specially described the electrical apparatus by which the 
spectroscope was kept at a uniform temperature during ex- 
posure of the plates. He also showed slides from a series 
of photographs of the spectra of stars taken with the instru- 
ment, with comparison spectra. 
DUBLIN. 
Royal Dublin Society, March 15.—Prof. J. A. McClelland 
in the chair.—Prof. W. F. Barrett, F.R.S., read a paper 
in continuation of his researches, in which he has the co- 
operation of Mr. W. Brown and Mr. R. A. Hadfield, on 
the physical properties of the alloys of iron. The paper, 
which forms part iv. of the series, deals with (a) micro- 
structure, and (b) thermal conductivity.—Mr. P. E. Belas 
read a paper on the structure of water-jets, and the effect 
of sound thereon. The paper was illustrated by photo- 
graphs.—Mr. J. J. Hutchinson described a simple arrange- 
ment for determining the maximum pressure of vapours at 
different temperatures. 
Paris. 
Academy of Sciences, April 5.—M. Mascart in the 
chair.—On the pathogenic agent of human trypanosomiasis : 
M. A. Laveran. A comparative study of Tr. gambiense 
of Ford and Dutton, and Tr. ugandense of Castellani, 
showed that grown under similar conditions the two are 
morphologically identical. The study of the pathogenic 
action on various animals, the action of human serum and 
arsenious acid, and the fact that animals rendered immune 
to the one are also immune to the other, also lead to the 
same conclusion. The author suggests that the name 
sleeping sickness, since it represents only the terminal 
phases of the infection, should be abandoned, adopting the 
name human trypanosomiasis, as applying to all the forms 
of the disease.—On a necessary condition for the stability 
of an unlimited vitreous medium: P. Duhem.—Observ- 
ations of the sun, made at the Lyons Observatory with the 
16 cm. Brunner equatorial during the fourth quarter of 
1903: J. Guillaume. The icsults are sur marised in 
