rrors. Worst of all, however,
was 'the destruction of the atmospheric air,' as Dr. Lardner termed it.
Elaborate calculations were made by that gentleman to prove that the
provision of ventilating shafts would be altogether insufficient to
prevent the dangers arising from the combustion of coke, producing
carbonic acid gas, which in large quantities was fatal to life. He
showed, for instance, that in the proposed Box tunnel, on the Great
Western Railway, the passage of 100 tons would deposit about 3090 lbs. of
noxious gases, incapable of supporting life! Here was an uncomfortable
prospect of suffocation for passengers between London and Bristol. But
steps were adopted to allay these formidable sources of terror. Solemn
documents, in the form of certificates, were got up and published, signed
by several of the most distinguished physicians of the day, attesting the
perfect wholesomeness of tunnels, and the purity of the air in them.
Perhaps they went further than was necessary in alleging, what certainly
subsequent experience has not verified, that the atmosphere of the tunnel
was 'dry, of an agreeable temperature, and free from smell.' Mr.
Stephenson declared his conviction that a tunnel twenty miles long could
be worked safely and without more danger to life than a railway in the
open air; but, at the same time, he admits that tunnels were nuisances,
which he endeavoured to avoid wherever practicable."

ELEVATED RAILWAYS.

In the _Gentleman's Magazine_ for June, 1830, it is stated:--"There are
at present exhibiting in Edinburgh three large models, accompanied with
drawings of railways and their carriages, invented by Mr. Dick, who has a
patent. These railways are of a different nature from those hitherto in
use, inasmuch as they are not laid along the surface of the ground, but
elevated to such a height as, when necessary, to pass over the tops of
houses and trees. The principal supports are of stone, and, being placed
at considerable distances, have cast-iron pillars between them. The
carriages are to be dragged along with a velocity hitherto unparalleled,
by means of a rope drawn by a steam engine or other prime mover, a series
being placed at intervals along the railway. From the construction of
the railway and carriages the friction is very small."

EVIDENCE OF A GENERAL SALESMAN.

The advantages London derives from railways, in regard to its supply of
good meat, may be gathered from the