q 
1871.] 11 [Reid. 
The value of R or the tractive power on a level, is 11,160 lbs., or 92; 
lbs. per ton. 
9.2 X 5280 
The angle of friction is_—* —— = 24.28 feet per mile. 
2000 
- oo ee 11160 : aie i 
The adhesion is ~ or nearly one-fifth of weight on drives. 
58,000 
From the data thus obtained a simple formula may be found to deter- 
mine the load of the engine on any given inclination, a. 
Let P = tractile power of engine on a level = 11,160 lbs. 
a == feet per mile of inclination. 
W! == weight of train on incline a, including engine and tender. 
Then W! X 9.2 = power required to move W! on level. 
9 
Ay Woe gravity on incline a, in tons or W! sigue a, in pounds. 
5280 : 5280 
irs MOO ai 
Oe Woe W'a — power of engine — 11,160 Ibs. 
5280 
Or Wi = 11,160" 
9.2+.38a, 
Ifa be supposed equal to 48.56, or twice the angle of friction, the load 
would be 404 tons nearly, or one-third the load on a level. 
On a grade of 80 feet the load would be 541 tons. The grade that would 
require double the power of a grade of 80 feet would be 84} feet. 
If the gross load of a train on a grade of 30 feet be 541 tons, the engine 
and tender being 63 tons, the cars and contents will weigh 478 tons, or if 
18,000 Ibs. be allowed for each car and 22,000 lbs. for load, the number of 
cars will be 27 and the net load 297 tons, weight of cars 243 tons, 
If the return cars shall be only one-fourth loaded, which is probably a 
full proportion for the Shenadoah Valley extension, the gross weight of 
the trains would be 380 tons. 
The inclination that would employ the full power of the engine in haul- 
ing 880 tons, would be 58 feet. 
The inclination that would employ the full power of an assistant engine 
in hauling a gross load of 380 tons, would be 130 feet, but allowance must 
be made for the weight of the assistant engine. 
’ 
The following description of Indian sculpture on the banks 
of the Monongahela River, by Jos. D. Reid, was received 
through Prof. Cope, accompanied by a drawing of the same. 
SKETCH AND Description or A CARvED Rock on the bank of the Mo- 
nongahela River, Pa., by Josepu D. Rein. 
(Read before the American Phiiosophical Society, Jan. 20, 1871.) 
The engraving represents the face of a large rock lying on the east 
bluff of the Monongahela River, in Fayette County, Pennsylvania, oppo- 
site the village of Millsborough and the mouth of Ten Mile Creek, 
