why should London lag behind the enterprise of country boards of
health 1
We left our heavily-weighted voyager off Picklow’s Point. I t had
now become so crowded with loathsome matters as to make one turn
sick to think of it. The once pure globule was floating sadly along,
when a boat rowed out from the shore. In it were two persons, a
gentleman and a Thames boatman—a calm, self-possessed man. The
scientist threw into the water a Winchester quart bottle, attached to
a cord. Our little limpid traveller floated into the vessel, with a
crowd of its dirty companions. The scientist pulled forth the bottle,
when it had filled, and labelled it thus :—“ Specimen collected from
the spot where the Princess Alice went down.” The much-tried
globule was carried in its prison-house to the laboratory of the chemist,
where in due course it was evaporated, released from the parasites and
débris that had clogged it, and permitted to return to the clouds from
which it had originally fallen, as pure and bright as nature made our
great river, the Thames, and as pure and bright as science can
maintain it, if science be permitted to do so. When will London
arouse herself to the awful significance of this true narrative of the
adventures of a drop of Thames water 1 Is the subject to degenerate
into a party question among politicians 1 Or shall we wait until some
new and terrible form of epidemic falls upon the great multitudes who
populate the banks of the river 1 We can solve foreign problems ; we
can regulate the Turk ; we can preside over the watery fortunes of the
Nile and the Ganges; let not our posterity have the right to curse us
that, though we illuminated its banks with electric lamps, we were
content to have our great and glorious river converted into nothing
better than a common sewer.
The second article is selected from among several
which appeared in Bradstreets. I t is dated January
15th, 1882:—
A VISIT TO ROTHSCHILD’S AND TO THE BRITISH
MINT.
London, January 5th.—From outside, neither the Royal Mint nor
Rothschild’s refinery present an imposing appearance. A street,
reminding one of the back slums of Calais, with quaint French signs,
French shops, and French people, leads up to a pair of large and
decayed wooden doors, the entrance to the works of Baron Rothschild.
An old man, with sabots on his feet, opens the door and ushers the
visitor into the presence ' of the director, a stout, genial-looking
Frenchman, who bows p great deal, and talks a great deal more.
Rothschild’s employés belong to “ the gay nation ” on the other side
of the English Channel. I had the privilege of being shown over the
large and interesting establishment of the world’s greatest financiers a
few days ago, and the following is a résumé of the processes in use at
Rothschild’s for purifying gold and silver :—
The gold as delivered is very impure. It contains large quantities
of silver, copper, iron, and other metals. The first operation consists
in melting the crude metal in a large clay crucible. By this means a
partial separation of copper is effected. The copper is oxidized, and,
rising to the surface of the molten metal, is skimmed by means of a
ladle. When as much copper as possible has been thus removed, the
molten alloy of silver and gold, still containing a little copper, is ladled
out and granulated by being poured into cold water. The granulation
is to give an increased surface for the action of the acid in the
subsequent operation. This granulated metal is then treated with
nitric or sulphuric acid, according to the method adopted in the
parting. Messrs. Rothschild use the latter process, which is generally
adopted in France, Germany, and Austria, because it is much more
economical than the nitric acid method. The sulphuric acid process
can be applied with success to the refining of silver containing only
0-0005 per cent, of gold ; but the metal for treatment requires to be
alloyed with a somewhat larger proportion of silver than is required in
the treatment of nitric acid. When the metal has been granulated as
described above, it is introduced into large leaden digesters, with
about two and one-half times its weight of concentrated sulphuric
acid, and it is very necessary to maintain the acid in excess in order
to retain the argentic sulphate, formed during the action, in solution.
The temperature is then raised to boiling, during which operation
volumes of sulphurous anhydride are evolved with the conversion of
the silver and copper into argentic and cupric sulphates respectively.
The chemical action continues from three to four hours, and the mass
is kept constantly stirred with a wooden pole in order to expose fresh
surfaces of metal to the action of the acid. The acid liquid is then
run off, and a small quantity of stronger acid added to the residue of
finely divided gold which is left in the bottom of the digester. The
gold is thereupon boiled up again, so as to insure the complete separation
of the sulphate of silver. In Messrs. Rothschild’s works two
products are thus obtained ; namely, finely divided, but almost pure
gold, and a solution containing argentic and cupric sulphates. - The
E