L 32 3 &s 
by 11 by 8 feet + SO (waste) 8448.10 per hour, 84480 per minute 
1408 feet. 
Consequently, 1647 per minute x 60 x 24 x 90 days=210.942,144 
1408 " X60x 16x90 '♦ =121,651,200 
Cubic feet, - 332,593,344 
Admittin!^ that the branches of the 
Little Conemaugh - 102.89 
And the stream near Lilley's mill 17 could be brought in, 
We must reduce them to the minimum of ^ or 30 feet. 
30 x 60 x 60 X 24 X 90 amounts to 233,280,000 
Shewingthequantity by reservoir to be 99,313,344 feet. 
One mile square 8 feet deep, with due allowatice for evaporation, 
the feeder being short, would probably be sufficient. 
It should not be exjtected that evaporation will cease during night 
in tunnels, as the air draws through them, nor tliat they will be ex- 
empt from soakage. The hydrostatic pressure which they are liable 
to produce on the fissures of roclis, may possibly occasion as much 
loss of water as they gain by the percolation fi om above their level; 
and as the Alleghany falls off very steep towards the east, compared 
to the declivity of the country west, it will be prudent rather to make 
their tunnel low than high ; though at the expense of its greater 
length. The commissioners state, that the mountain, in many places, 
exhibited strata of rock in a horizontal position, mixt with clay, 
which are not unfiworable indications. 
Section 3. The country down the valley of the Juniatta continued 
generally to wear a favorable appearance, unless it be where the 
mountains range transversely to the coui'se of the river, when the 
shores rise steep and high, covered with a vast aggregation of the 
fragments of rock. These, however formidable to the eye, are to be 
considered rather as masses of rough materials broken up to hand, 
in readiness for the high and strong walls with which the canal will 
have to be supported, above reach of the freshets. In this place it 
w ouid seem an omission not to notice the improvement of the Susque- 
hannah down to the Chesapeake Bay (in progress by the joint exer- 
tions of Maryland and Pennsylvania.) The commissioners, in their 
report to tl»e Secretary of tlie Commonwealth of Pennsylvania, ex- 
press great satisfaction that the commissioners of both states, ^''are 
unanimously of opinion tiiat an ascending navigation is practicable, 
altliough tliere may be some difference of opinion as to the ulterior 
measures tiiat may be most expedient, and the expense required to 
accomplish it.** The commissioners have taken considerable pains to 
form an opinion upon the best gi-ound within their power, of the pro- 
bable expense of the ascending navigation, at the same time they 
would have been highly gratified to have had the opinion of a skilful 
engineer. They have, however, come to the conclusion, that a less 
