213 
NOTES ON A VISIT TO THE CHANNEL TUNNEL. BY ARNOLD 
LUrTON, M. INST. 0. E., F.G.S., ETC. (PLS. VilL AND IX.) 
The writer is indebted to the paper of Mr. C. Tylden Wright, 
read at the North of England Institution of Mining Engineers ; and 
to other sources for much of the information contained in this paper. 
From these, as well as from his own notes, he has obtained various 
details, and has prepared the diagrams to illustrate his remarks. 
Last November (1882), the writer was invited to accompany a 
party of Mining Engiueers, to visit the works of the Channel Tunnel 
near Dover. A shaft 163ft. deep is sunk between the Railway and 
the sea-shore, and from the bottom of this, a small tunnel 7ft. in 
diameter is driven a distance of 2,000 yards under the sea, in the 
grey chalk, may be described either as a soft stone or as a hard clay. 
The plan and section will explain their relative position. 
It is proposed to drive the tunnel with an inclination down-hill 
of 1 in 80 from the shore at each end, for a distance of 2 miles, and 
then to drive it with a rising- gradient of 1 in 2,000, to the 
centre of the channel, so that the water met with under the sea, may 
run to within two miles of the shore, from which point it may be 
pumped in pipes, or conveyed by a level heading to the shafts, and 
there pumped to the surface. 
The heading is driven by the machine of Messrs. Beaumont & 
English, which cuts away the whole face of the headings, and delivers 
the fragments at the back of the machine ; it will advance f inch a 
minute (as witnessed by the writer), this is equal to 37^in. an hour, 
viz. : 1 yard an hour or 24 yards a day, which equals 4;^ miles a year 
without working on Sundays. This, with an equal rate of prog'ression 
on the French side, amounts to 8J miles a year, and the distance of 
22 miles (21 yet to drive) will be accomplished in 2^ years. It is 
quite reasonable to suppose that this may be done, because the machine 
has been driven at a greater speed than given above, upwards of 40 
yards having been driven in one day. It is intended to drive the 
tunnel at such a gradient that there shall not be less than 150ft. of 
strata between it and the deepest part of the sea. The stratum of 
grey chalk is 226ft. thick, and extends all the way from the French 
to the English coast ; it is a water-tight stratum ; at the English 
