The Sun.
London, England, 1868-02-14 00:00:00

ROYAL IN.S7 ITUTION.

Professor Tyndall is now delivering a course of
experimental lectures, every Tuesday and Thursday
afternoon, on " The Discoveries of Faraday." In
the lectures already delivered he has rapidly and
clearly taken his hearers over the ground of the
many discoveries of Faraday in the phenomena of
electric induction, electro-magnetism, and magneto-
electricity, up to the construction of the powerful coil
machines of the present day. As to what electricity
and magnetism may be, and what takes place iii
wire when electricity travels through it, the
lecturer said nothing ; for little is known
about these mysterious forces, and all philo-
sophers can do at present to unvail these secrets of
nature is to find out fresh phenomena and to mul-
tiply the number of ascertained facts. In many of
the experiments Professor Tyndall employed a re-
markably sensitive galvanometer, which gave a
deflection when a single loop only of copper wire
was passed over a by no means powerful bar
magnet. To enable the audience to see the
movements of the little needle, the lecturer con-
densed upon it the rays from an electric lamp ;
a large lens was then placed above the galvano-
meter, au enlarged image of which was thereby
thrown upon the screen, the upward direction
of the rays being changed by means of a
mirror placed at an angle of about 45 degrees.
He also exhibited at work what is probably the
most powerful induction coil in England; it is the
property of Mr. Gassiot, F.R.S., was made in Ame-
rica, and gives a spark nearly a foot long. One of
the most curious experiments exhibited consisted in
filling a small tube of copper with fusible metal.,
and causing it to spin round with great velocity
between the poles of a powerful elec ro-magnet,
which poles it did not touch. Copper so placed
has its rotation strangely retarded, as if surrounded
by cheese or butter, and the motion, overcom-
ing this invisible frictional agent, generates so
much heat in the copper tube that the
fusible metal inside is melted. Yesterday
afternoon Professor Tyndall exhibited many of
Faraday's discoveries in the decomposition
of liquids by the voltaic current. Last Fri-
day Professor Huxley, F.R.S., lectured on the
" Animals most intermediate between birds and
reptiles." He explained that he believed in the
doctrine of " evolution"—that is to say, that the
long action of causes now at work has alone created
the great differences in animals which we see at the
present day. He then, by exhibitions of skeletons
and drawings, showed in what particulars every
living bird differs from every living reptile. He
next went back to the first great geological period
—a period so remote, he said, that man can
scarcely form an idea of its antiquity when com-
puted by our ordinary methods of measuring
time, and acknowledged that in this geologi-
cal period the same wide distinctions as at
the present day separated birds and reptiles. But,
going farther back, through another vast cycle of
ages, he showed that the one solitary bird found
belonging to that epoch has many strong reptilian
characteristics, including claws in its forelegs or
wings. The reptiles, of which there are numerous
remains, had many of them bones like those which
are now found only in birds, and never in reptiles.
As, then, some widely different animals converge in
anatomical structure the farther they are traced in
geological history, so, he concluded, similar animals
may diverge into dissimilar animals under na-
tural causes acting during vast periods of time.
Another course of lectures is now being given on
Saturday afternoons, by Professor Roscoe, on
" Chemistry."