, 1865-07-28

with the man at the bottom. Others are
for use on railways; others in ships for
the delivery of orders from the deck to
the engine-roOm. One Of the latter was
the more noticeable, as it has a contri-
vance for making known on the deck in
simultaneously whether the order to re-
verse the engines has been obeyed or not.
But while all possible contingencies or
services seem TO be provided for, there
was no contrivance or apparatus for COM
munlcatlng between the passengers of a
railway-tra!n in motion and the guard Oh
engine-driver. 1t is by no means credita-
BILE to the inventive genius of the day
that this reproach should still be made
against US.
The numerous Improvements made in
that but recently-lnvented instrument
the spectroscope, are good evidence Of
the advances made in optical science for
while some specimens contain combina-
tions for observing all the phenomena Of
light, others are so small and portable,
that they can be carried in the pocket;
and this instrument can now be used in
combination with the telescope or the
microscope, analysing the sun and fixed
stars, the largest and most remote OBJ
jects, as well as the smallest and nearest.
In this branch Of art, Mr.. John Brewing
has achieved a weIl-descrved reputation
as a manufacturer.-A good example of
IN application Of optical science was
shewn by what is called the crystal-cube
portrait. The cube is formed of two
prisms; a Photographic portrait is fixed
to the back of one of the prisms, and to
the side of the other and being reflected.
on the two inner surfaces, they there
blend and appear as one, but in lIfelike
relief. A portrait Of Lord Brougham,
taken a few months ago, and mounted in
this way, represented the venerable phi
Iosopher with an appearance of reality
that excited surprise and admiration-
Another optical continuance is the dis
solving stereoscope, in which, while the
spectator is looking at the pictures, one
subject fades, as it were, into another
with very pleasing effect.
Mr.. Sorby Of Sheffield has done service
TO metallurgy by his researches into the
microscopic structure of iron and steel,
all of which have an important bearing
On the question Of the strength and du-
rability Of iron used for railway purposes.
u lCALuIS Vi lIOA duu SISCI dibCAS WILL
~long-continued use and repeated shocks,
and there is no instrument so likely to
be useful in detecting the alteration as
the microscope. The same gentleman
shews how the s~pectroscope may be en-
ployed in the detection of blood-stains on
linen even when faint; and it may be
that we shall some day hear that his me-
thod has been tried in the investigation
of suspected crime.
Ifto all these inventions we add instru-
ments for showing various phenomena of
polarisation of light-an apparatus for
producing a vacuum by falling mercury,
more effective than the airpump-an in
strument for showing the development of
heat in growing plants-rare drawings by
the old masters, lent by the Queen, and
paintings, drawings, and sculptures by
modern artists, it will be understood that
a Conversations at the Royal Society is
not a mere dilettante affair, but an enter
tanning demonstration of the progress of
art, science, and philosophy. Consider
ing the benefits that London has derived
from applications of science, we can re-
cn0niSa the SioniHcarca IF a hanauof riv-