Trans. N. Y, Ac. Sez. 156 Apr. 17, 
stances of these grounds of criticism were given as examples, and of the 
natural difficulties, moreover, which often involve great and unavoidable 
delays and irregularities in the transit of both passengers and mails. 
Under these circumstances, the great desirableness of some improved 
means of travel is apparent at a glance, when it is remembered that a 
country of 30,000,000 of inhabitants is to be connected with a continent 
of 300,000,000, and that some 700,000 passengers annually make this 
passage. 
If the commercial aspect be regarded, it is found that the yearly 
interchange of products between England and the continent amounts 
to a hundred millions of pounds sterling in value, and employs vessels 
aggregating a tonnage of ten millions. There could be no question of 
the financial success of such an undertaking as the proposed tunnel, 
where so large a business in both freight and passengers is subjected 
to so many inconveniences. If America had been similarly situated, 
such a work would long since have been accomplished; but the con- 
servatism and the political anxiety of the English people have interposed 
serious obstacles. 
Some seven years ago the proposal was first discussed, and the financia] 
and engineering possibilities were largely debated, but no political diffi- 
culties were then raised. Only of late has this aspect been presented, and 
a formidable opposition made to the construction of the tunnel, on the 
part of both the people and the Parliament of England. This objec- 
tion the lecturer considered most unwise and unjustifiable, a selfish 
hindering of a great enterprise of general importance and advantage. 
The St. Gothard Tunnel, or the railway over the Pyrenees, would be 
open to the same objection of a possible political danger; but none of 
the nations thus connected had for that reason opposed these great 
works of intercommunication. Nothing could be easier or simpler 
than to guard the entrance to a tunnel, especially when that tunnel 
lies beneath the sea, and could be flooded and closed at the first inti- 
mation of a foreign invasion. 
Turning to the scientific aspect of the work, reference was made to the 
character of the material in which the tunnel is to be wrought. This 
is found to be chalk throughout, the well-known chalk of the Dover 
cliffs extending under the channel all the way. The work of excavation 
is therefore easy; the question might arise, however, how far this soft 
rock would prove impervious to the water. This had been tested by 
careful experiments; and it was proved that, even under heavy pressure, 
a small thickness of chalk allowed scarcely any perceptible passage to 
water, 
The construction of the tunnel was next described, and illustrated by 
drawings. Its general section-form would be that of a low horse-shoe, 
