So, it would seem, firstly, that the chief condition
is satisfactorily ensured, and that the geological
formation of the sea's bed is such as to
admit of the excavation of a tunnel through
the lower grey chalk; and secondly, that it
is not necessary to go to a depth unsuitable
for railway traffic. It is calculated that the
approaches to the tunnel can be constructed at
gradients not exceeding one foot in eighty.

The next point of paramount importance to
the travelling public, is the question of the
safety of the tunnel when made. The dangers
most carefully to be guarded against, are two:
any possible irruption of water from the sea,
or from unexpected land- springs; any
deficiency in ventilation.

There need be little apprehension of spring
waters. The difficulty in sinking wells through
the chalk, on either side of the Channel, has
been, not to keep the water out, but to get at it.
A well sunk at Calais to the depth of a thousand
feet, failed to find water at all; and in sinking
deep wells at Dover, water was not to be
found either until the driving of headings was
resorted to. Even the Castle well, which is
three hundred and sixty-three feet deep, and
below high-water mark, is pumped dry by
a thirty horse-power engine in three hours.
Firm chalk, in fact, not split by fissures and
defects, is not a good water-conducting stratum.
In the Paris district, for instance, the artesian
wells have been sunk through the chalk, which
is there at least thirteen hundred feet thick.

If the dangers of land-water, so to speak, be
thus slight, the dangers to be apprehended from
sea-water appear to be even slighter. The
proposed excavation would be nowhere nearer
the bed of the sea than a hundred feet.
It would seem to be most unlikely that the
sea should make its way through this thickness
of chalk. Many Cornish mines extend
for considerable distances below the sea,
and their comparative immunity from inroads
of the sea is remarked by Pryce in his treatise
on Minerals, Mines, and Mining, published in
1778. His explanation is, that such fissures as
may possibly exist, and which might be
permeable by water, have been, in long course of
time, filled up by some impervious substance
deposited by the action of the water itself, and
thus a massive ceiling, as it were, of concrete
has been formed above the mines. In the
opinion of the eminent engineers who are
advising Lord Richard Grosvenor's Executive
Committee, this is probably the case in the
Channel grey chalk; and looking at this
circumstance and at the nature of the chalk,
they do not anticipate being troubled with
more water than can be easily disposed of by
ordinary pumping operations.

The financial part of the question may be
considered with the ventilation question. At
present, with the imperfect data we have to
go upon, it is matter of great difficulty to say
what such an excavation would be likely to
cost. Given no unforeseen impediment, given no
incursion of unexpected water, given no break
in the strata, a trustworthy calculation might
be arrived at. But in the face of the unknown
possibilities lying at the bottom of the sea, the
committee wisely abstain from yet addressing
themselves to the cost of the tunnel, or to
the commercial questions of profits, capital,
and dividends. They propose, first following
the suggestions of their eminent scientific
advisers, and the original proposal of Mr. Low
to commence their work by sinking pits
on each shore, and by driving thence two
small headings, or galleries, from each country,
connected by transverse driftways. Ventilation
would thus be secured in the manner
customary in coal mines and works of a similar
nature, and the feasibility or otherwise of
connecting England and France by a submarine
tunnel would be proved. When this is done,
or when so much of it is done as fairly to
prove the case, then the committee will
consider the time arrived for carrying out their
great enterprise in all its magnificent details.
All points relating to the permanent tunnels
would be settled by the experience gained in
making the headings. The point of ventilation
could be satisfactorily determined in the
preliminary workings. It is computed that to
preserve perfect ventilation in the completed
tunnel, currents of air should be driven through
it at the rate of ten miles an hour by steam
engines of from six to seven hundred horse power.

The cost of these preliminary headings is
reckoned, upon careful calculation, at two
millions sterling; and to that amount the loss, in
the event of non-success, would be confined.
For the purpose of raising this sum of money,
the committee ask for a joint guarantee from the
two governments, of interest at the rate of five
per cent on any amount they shall expend up
to two millions that is to say, for an annual
guarantee of fifty thousand pounds from each.
It is not necessary that the whole of the two
millions should be expended; for should the
guaranteeing governments be dissatisfied with
the progress of the works, or with their nature
or results, they would at any time have power
to stop the works. At the worst, and supposing
the whole sum to be expended and no
satisfactory result attained, fifty thousand
pounds a year for a certain number of years
(for the operation of a sinking fund would in
process of time replace the capital) is not a
very large sum for a great nation to expend in
so great an attempt. If the preliminary headings
turn out successful, there will be no
difficulty in raising the capital necessary to
complete and to work the tunnel; and the
guaranteeing governments will speedily be
released from their obligations.

As relates to the French government, the
committee have, it is understood, every reason
to be satisfied with their prospects. On this
side of the Channel things progress more
slowly, and Circumlocutionism is a little difficult
to move. The matter has lately been brought
before the President of the Board of Trade,
and will probably, at no distant period, assume
a definite shape. The six gentlemen who