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Nature
(Thursday, November 4, 1869)

Geikie, Arch.
The meeting of German naturalist and physicians at Innsbruck, Tyrol,   pp. 22-23


Page 22


NVA TURE
[N"oV. 4, I 869
spontaneous motions of particles of matter, whether in
the state of gas or in the liquid state.
   It was known that I part by weight of hydrogen occupies
the same volume as i6 parts by weight of oxygen when
measured at like temperature, and under like pressure.
Chemical investigations prove that these equal volumes
of the two gases contain the same number of atoms. We
also know that the atoms in such a gas are in rapid motion,
and resist the pressure to which the gas is at any particu-
lar time exposed, by striking against the surface which
presses them together with force equal to that which presses
them together.
  Thus a given volume of hydrogen is maintained against
the atmospheric pressure by an energy of atomic motion,
equal to that of the same volume of oxygen. Each atom
of hydrogen accordingly exerts a mechanical energy equal
to that of each atom of oxygen; but wve have seen that
the hydrogen atom is much lighter than the oxygen atom,
and accordingly it must move with much greater velocity
than the oxygen atom.
  Now Graham allowed hydrogen to escape through a
vcry small hole in a plate of platinum; and allowed oxygen
to escape under similar circumstances. He found that
each hydrogen atom moves out four times as fast as each
oxygen atom. His experiments were so arranged as to
enable him to measure the relative velocities of certain
motions of the atoms-motions not imparted to them by
any peculiar or unnatural conditions, but belonging to
them of necessity in their natural state. He found,
moreover, that heat increases the velocity of these atomic
motions, whilst increasing the force with which a given
weight of the gas resists the atmospheric pressure.
  The study of the condensation of gases by solids, and
the combination of soluble compounds with membranes
led him to discoveries which are likely to be of great
value to physiologists in explaining processes of absorption
and secretion.
  Thus he found that oxygen is absorbed to a greater
extent than nitrogen by caoutchouc, and that when a bag
made of a thin membrane of this substance is exhausted
by means of a good air-pump, the oxygen and nitrogen
diffuse through it (probably as condensed liquids), and
evaporate inside the bag in different proportions from
those in which they are present in air; the oxygen rising
to over 40 per cent. of the diffused air. Again, a mixture of
hydrogen and oxygen was separated almost completely by
the action of palladium, which condensed the hydrogen in
very large quantity, and the oxygen very slightly.
  Perhaps the most remarkable substances discovered in
the course of his experiments on diffusion, were the soluble
modifications of tungstic and molybdic acids, ferric oxide,
&c., and the process by which these bodies were obtained
was, perhaps, the most instructive part of the result;
proving, as it does, that in their salts, these bodies have
properties different from those which they normally
possess in the free state ; and retain them when the other
constituent is removed by a sufficiently gentle process.
  Another remarkable fact whichbears on a most important
theory, is the separation effected by Graham of potassic
hydrate and hydric sulphate, by diffusion of potassic sul-
phate in aqueous solution-a fact which requires us to
admit that the solution of the salt in water contains those
products mixed with one another; just as much as the
experiment of diffusing air through a porous clay pipe,
and getting its constituent in a different proportion from
that of the original air, proved that air is a mixture and
not a compound of the two gases.
  In his later researches Graham was assisted by Mr.
W. C. Roberts, and cordially acknowledged the zeal
and efficiency displayed by that able young chemist.
Graham's scientific influence extended beyond his re-
searches; for, on the one hand, his lectures for 18 years at
University College were remarkable for logical accuracy
and clearness of expositions and were highly valued by
those who had the privilege of hearing them.  On the
other hand, his " Elements of Chemistry" is a masterly
exposition of the best known facts of the science and of
chemical physics. It was translated into German, and
afforded at that time the most philosophical account of
the working and theory of the galvanic battery.
  In many of his ideas Graham was in advance of his
contemporaries, and it might be difficult to find a chemist
who has dealt more cautiously with general questions and
delicate experimental operations,-or one whose results, in
each direction in which he has worked, may more safely
be expected to stand the test of future investigations.
                                 A. W. WILLIAMSON
THE J1EETIiNG OF GER1IAN NATURALISTS
AND PHYSICIZiZA     S a- T IZAWVSBRUCK, TYROL
   ROM the i8th to the 24th of September last the little
F town of Innsbruck wore an air of unwonted bustle
and excitement. Its population, already augmented by
the usual throng of summer tourists, was swelled by the
advent of some'vhere about 8oo additional visitors-pro-
fessors, doctors, directors, men of all sciences, often with
their wives and daughters, who had come from all parts
of Germany to attend the forty-third Meeting of the
German Naturalists and Physicians.   These meetings
resemble those of our own British Association, though
they differ in several very characteristic respects. One of
the first contrasts to strike an Englishman is the entire
absence of private hospitality. Everybody, so far as we
can learn, is in private lodgings or in a hotel; and there
are no such things as dinner-parties. Although our own
customs in these respects are certainly very pleasant, there
can be no doubt that the German fashion leaves the
visitors more freedom, and allows them much more oppor-
tunity of seeing and talking with the friends they most
wish to meet. With us it is no easy matter to get together
a party of chemists, or geologists, or physiologists, to hold
a social gathering after the labours of the sections are
over. We are all either staying with friends, or invited to
dinner, or engaged in some way. But at the German
meetings such social reunions are one of the distinguishing
features. One o'clock in the day brings with it the
necessity for dining, and numerous dinner parties are im-
provised there and then; friends of like tastes, who have
not met perhaps for a year before, adjourn to a restaura-
tion or kaffee-haus, and while eating the meal have a
pleasant opportunity of comparing notes, and discussing
questions which have in the interval arisen.
  Another feature of contrast is in the length of time
devoted to the sitting of the sections. At the British
Association the sections open their sittings at eleven in the
forenoon ; and the work goes on steadily all day without
intermission till four or five o'clock in the afternoon.
But, in Germany, the sittings commence sometimes as early
as 8 A.m., and are frequently over by ten or eleven o'clock,
leaving the rest of the day for some short after-dinner
excursion, or for general miscellaneous intercourse among
the members. In fact, the German meetings are designed
less for the purpose of bringing forward new scientific
work, than with the view of affording to men of science
opportunities of becoming personally acquainted with
each other, and of discussing the value and bearing of
recent contributions to knowledge. Hence, the papers
which are brought before the sections, contain, to a large
extent, outlines, summaries or notices of recent researches,
and exhibitions of books, maps, memoirs, specimens,
experiments, &c., which have recently attracted notice.
  In our British Association gatherings, there is probably
more hard work than in those of our German brethren,
and I daresay there is as much opportunity for sociality
as suits our national temperament. For our Association
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