7O 
NATURE 
[May 15, 1902 
followers, ‘I suppose they will end some time, but I confess 
I see no reason why they should.’” Dr. Gilman concludes 
his article with the following wise words :—‘‘ In the conduct 
of a university, secure the ablest men as professors, regardless 
of all other qualifications excepting those of personal merit and 
adaptation to the chairs that are to be filled. Borrow if you 
cannot enlist. Give them freedom, give them auxiliaries, give 
them liberal support. Encourage them to come before the 
world of science and of letters with their publications. Bright 
students, soon to be men of distinction, will be their loyal 
followers, and the world will sing a loud Amen.” 
SCIENTIFIC SERIAL. 
Memoirs of the Kazan Soctety of Naturalists, vol. xxxv.— 
Researches into the Protozoa of the Black Sea, by R. Minkiewicz. 
The organisation, the multiplication and the systematical 
position of Euplotes (Ehrbg.) are discussed.—Materials for the 
knowledge of the soil and vegetation of western Siberia, by A. 
Gordyaghin. This is the second and last part of a very valuable 
work which was began in a previous issue of the same periodical 
(vol. xxxiv.). The fir, Scotch fir and birch forests, the mutual 
relations between the chief arborescent species, and the Steppe 
vegetation are discussed in this part, which contains also a large- 
scale botanical map of the western portion of the basin of the 
Irtysh and a full index.—The physicochemical structure of the 
chlorophyll grain, by M. S. Tsvett. Experimental researches 
and critical review of the work hitherto done.—Botanic-geo- 
graphical researches in the province of Saratov, by B. Keller. An 
interesting general review of the vegetation (summary in German) 
and a list of 987 plants belonging to the flora of Saratov are 
given.—On the soils of south-eastern Russia, by A. Ostriakoff, 
being descriptions and chemical analyses of salt-bearing soils of 
sovthern Samara. 
SOCIETIES AND ACADEMIES. 
LonpDon. 
Physical Society, May 9.—Prof. S. P. Thompson, presi- 
dent, in the chair.—Dr. P. E. Shaw exhibited a simple electric 
micrometer. Two years ago, Dr. Shaw described an instrument 
with which he measured very small lengths by the application of 
electric contacts, and the micrometer shown was a simple form 
of the original apparatus. A screw, fitted with a milled head, 
turns ina fixed nut, and its lower end presses upon the ex- 
tremity of the long arm of alever. A metal point is attached 
to the short arm, and the distance through which it moves, on 
turning the milled head, can be deduced from a knowledge of 
the pitch of the screw and the ratio between the arms of the 
lever. In using the instrument, this point isalways brought up 
to a metal surface, and the contact is accurately determined by 
the telephonic arrangement described in connection with the 
original micrometer. Dr. Shaw illustrated the use of the in- 
strument for measuring small lengths by describing the following 
eight applications to ordinary laboratory measurements :—(r1) 
The measurement of the thickness of plates, films or fibres. 
The object is placed between two metal plates. The point or 
the micrometer is adjusted to touch the top plate and the read- 
ing taken. The object is removed, the point is again brought 
into contact with the top plate, and the difference between the 
readings in the two cases gives the thickness of the film. (2) 
The determination of Young’s modulus by the elongation of a 
wire. Dr. Shaw described experiments on two wires, each 
24 metres long, hanging side by side, one of copper and the 
other of steel. The wires terminated in horizontal plat- 
forms to which the stretching weights were attached. 
The base of the instrument rested on one platform, 
while depressions of the other, due to loading, were 
measured, In this way any error, on account of the bending of 
the beam from which the wires were hung, was eliminated. 
(3) The determination of Young’s modulus by the bending of a 
beam. (4) The determination of simple rigidity by a static 
method. Observations were made upon a rod held horizontally 
by rigid wall brackets. One end of the rod was fixed and the 
other held in position by a pin pressed into a hole in the end of 
the rod. From this end an arm projected outwards. Weights 
were applied to the extremity of this arm, and the twist 
NO. 1698, VOL. 66] 
measured by observing with the micrometer the movement of 
the end of the arm. (5) Application to the extensometer. 
(6) Measurement of thermal expansion. (7) Microscopic 
measurements. In measuring the diameter of a capillary tube, 
the cross wire of the microscope is made to touch one side of 
the tube, and the point of the micrometer is brought into 
contact with the metal stage. The stage is then moved by a 
screw until the cross wire comes to the other side of the tube. 
The micrometer point is moved into contact again, and the 
difference in the readings gives the diameter of the tube. 
In this measurement the full magnifying power of the microscope 
is uullised, and the work of moving the stage is performed by 
a rough screw. (8) The direct measurement of the wave- 
length of light. Newton’s rings are formed by a convex lens 
and a piece of plate glass. The convex lens is fixed to the 
short arm of the lever, and the distance through which it must 
be moved to cause a certain number of bands to appear at the 
centre gives a means of calculating the wave-length of the 
light employed.—Papers on the conservation of entropy, 
by Mr, J. A. Erskine, and rational units of electromagnetism, 
by Sig. G. Giorgi, were postponed. 
Chemical Society, April 30.—Prof. Emerson Reynolds, 
V.P.R.S., in the chair.—The preparation of absolute alcohol 
from strong spirit, by Dr. Young, F.R.S. The 4 or 5 per cent. 
of water remaining in the strongest rectified spirit procurable by 
distillation can be removed by adding to it a volatile liquid 
capable of forming with alcohol and water a ternary mixture 
boiling below 78°*3 C. and distilling. Benzene is a suitable 
substance for this purpose, the ternary mixture so formed boiling 
at 64°.85. The alcohol thus obtained contains a trace of benzene, 
which in turn can be removed bya redistillation with pure hexane. 
—On the properties of mixtures of the lower alcohols with water, 
by Dr. Young, F.R.S.,and Miss E. C. Fortey. Methyl alcohol 
can be prepared in an absolute condition by simple distillation 
through an efficient still-head. The higher homologues, such as 
isopropyl, propyl and tertiary butyl alcohols, can be dehydrated 
by addition of benzene and redistillation. The constant boiling 
mixtures of these alcohols with water are not definite hydrates — 
On the properties of mixtures of the lower alcohols with 
benzene and with benzene and water, by Dr. Young, F.R.S., 
and Miss E. C. Fortey. Among the lower alcohols of the 
paraffinic series, all except isoamyl alcohol form constant boiling 
mixtures with benzene, but beyond the amyl alcohols this 
phenomenon no longer occurs; ethyl, propyl, isopropyl and 
tertiary butyl alcohols alone ferm constant boiling ternary com- 
pounds with benzene and water.—Fractional distillation as a 
method of quantitative analysis, by Dr. Young, F.R.S., and Miss 
E. C. Fortey. When a mixture which tends to separate into two 
components is distilled, the portion of the distillate obtained below 
the temperature midway between the boiling points of the two 
constituents is almost exactly equal to the weight of the more 
volatile component of the mixture. This principle can also be 
extended to ternary mixtures.—On the vapour pressures and 
boiling points of mixed liquids, by Dr. Young, F.R.S. 
Mixtures of bromo- and chloro-benzene exhibit a close agreement 
with van der Waals’s law, which states that ‘‘ the relation between 
vapour pressure and molecular composition of mixtures of liquids 
having equal critical points and in which a@,.o= ,/a, a (where 
@.9 represents attraction of unlike molecules and a, and a, the 
attractions of like molecules) is represented by a straight line.”— 
‘The correction of the boiling points of liquids from observed to 
normal pressure, by Dr. Young, F R.S. An extension and 
improvement of Craft's table of constants of correction.— Vapour 
pressures and specific volumes of isopropyl isobutyrate, by Dr. 
Young, F.R.S., and Miss E. C. Fortey. These constants have 
been determined on a pure specimen of this ester prepared by 
electrolysis of potassium isobutyrate.—The preparation of highly 
substituted nitroaminobenzenes, by Dr. Orton. The author has 
devised a method of preparing aromatic nitroamines by the 
action of nitricacid on amines dissolved in acetic anhydride, and 
has by this method isolated and characterised a number of 
these substances.—The atomic weight of tellurium, by Dr. 
Scott, F.R.S. When tellurium is treated with methyl iodide, 
it forms a trimethyl tellurium iodide which crystallises well and 
affords a convenient method of comparing the combining weight 
of tellurium with that of iodine which is accurately known 
from Stas’s determination. The ratio thus found indicates that 
the atomic weight of tellurium is about 127°75 —Nitrogen 
bromides containing the propionyl group, by Dr. Chattaway. A 
