no 
Rev. Mr. Adamson on Rail-Roads. 
The same formula will afford us the means of discovering 
what ought to be the inclination of a rail-road, when the traffic 
in one direction bears a known proportion to that returning in 
the opposite one. If we make the ratio of these loads, ex- 
pressed as multiples of the weight of the engine, to be q : 1 ; 
then, taking the values of sin i from the equations, with the 
upper and lower signs separately, we have the resulting equa- 
tion, 
sm 
I X X (a +"0 ±tj \x X a +"0 “ ~ 
q — 1 V n/ v 4 \q — 1 n/ n 
if q = 2, and the other symbols express the same quantity, as 
before, 
1_ 
666 
Sin i — nearly ; 
in this case W = 6, and q W =12; or an engine which, on 
a level rail-road, drags eight times its own weight of load- 
ed carriages, will, on an inclination of 1 foot in 666, drag up 
six times its own weight, and will drag down twelve times 
its own weight. If q = 4, which is nearly the proportion when 
loaded carriages descend and empty ones alone return, the in- 
clination required is about ~ ; in this case the weight dragged 
up ought to be nearly 4.8 times the weight of the engine, and 
that taken down the inclination ought to be rather more than 
nineteen times the weight of the engine. If E — 7 tons, the 
weight of the empty carriages will be about 33^ tons, and the 
weight of the goods conveyed on them will be about 100 tons. 
From the great effect which the weight of the engine and 
load, independent of their friction, has in diminishing the pro- 
gressive effect on inclinations so small, we may perceive how 
little can be gained by enabling the engine to ascend greater 
inclinations ; since we must make a great disproportion be- 
tween either the loads, on a level and on air inclination, or their 
velocities. 
(To be continued.) 
