59 C 32 ] 
state of the season allowed tlieni to make on the other !icciu>n of Ihr 
canal; beginning by the sumntit level on the ridge of the Allcgiiany. 
A prollle of the Alleghany mountain has been taken, running IVom 
Selby's mill: the line of section making aii angle of SIMS' \\it!i tlie 
meridian. By that means a point was lixed in Blair's <jap liun, a 
branch of the Beaver-dam, on a level with Selb>'s Mill. The hor- 
izontal distance between them, uas t'onnd to be 4 miles 698 yards; 
If a tunnel was run in this direction and on this level, with deep cuts at 
both exti'cmilies and to the depth of 35 feet, it would have nearly 4 
miles in lengtli, its bed would be 754 feet below the summit of the 
mountain, 1S31 feet above the ocean, and 1,075 feet above the Ohio 
at Pittsburg. By raising the level of this tunne!, its lenglli would he 
diminished, but it would augment the lockage and be su])plicil with 
less water. By lowering it, it would have more water and less locl:- 
age, but its length would be augmented. Accurate and detailed esti- 
mates can alone enable us to compare the expense of a foot of tun- 
nelling with that of a foot of lockage, &c. But for our present object, 
we will merely state that a tunnel of 4 miles in lengtli is the siiortesl 
which in this ])art of the AUegliany can unite its eastcrji ii\u\ westcj-n 
watei's; and that, by lowering it 70 feet, which would diminisii its 
lockage 140 feet,and augment its lengtli about 1 mile, it is probable tliat 
the summit level might be abundantly supplied by the constant liow- 
ing springs of its eastern and western streams, formed into reservor.s. 
"VTe will add that the summit of the Alleghany is, from the prcccdijjg 
data, 2,585 feet high at the spot where the profile was taken, 
As to the other sections of the canal, tlie surveys and levels cave 
the following results for the total amount of tlieir leiigtlis and lock- 
age. 
From PUtsburi;^ to the western extremity of its summit 
level, tunnel length, .... 112 miles, ascent 1,075 feet. 
Length of summit level tunnel, - - - 4 " 
l-'rom its eastern extremity to Miildletown, - - 153 " descent 1,608 " 
From Middleiown to the, Schuylkill, - - - 110 " as. Sides. 675 '* 
o79 ■j,o58 
We have not examined the line of canal which might lead froiu Har- 
risburg to the mouth of the Susquehannah; it did not enter into the 
th.ose operations which wc performed in co-operation with the Penn- 
sylvania Canal Commissioners. From the levels run, in 1823, foi- 
the state of Maryland, by Capt. Hartman Bache, United States' To-' 
pographical Engineer, and Lieuts, Eakin, Graliam, and Boyce, of 
tlse United States' Artillery, and the surveys directed by Mr. Geddcs, 
a canal, descending from York-Haven to Havre-de-Grace, at the moutli 
of the Susquehannah, would require 272 feet lockage, on 55| miles in 
length. If led to Harrisburg, its total length would be 62 miles, 
and its lockage 297 feet at most, as Harrisburg is 297 feet above tide 
water. Tliis line would have over that from Middletown to the 
Schuylkil!, the following advantages: 48 miles less in length to reiich 
tide water; about 378 feet less of lockage; a more plentitul supply of 
water, and tl-' saving of about two miles of tunnelling. But in these, 
