American watchman and Delaware advertiser. [volume] (Wilmington, Del.) 1822-1828, 1825-05-24

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In this computation, it is assumed that The draught
IF horse is the same at two, four, six, and eight
miles an hour. Ia fact, however, its dralsht dl 4
ninishes very rapidly as its velocity increases, a.
great portion of its strength being exhausted in
supporting lis velocity. II l00lb. measure the force
OF traction of horse, when travelling at the rate of
Two miles an hour, then will this power be reduced
Cab. when lie travels at the rate OF four miles an
hour and for higher rates OF travelling 1t diminish
es still more rapidly. Here the draught OF horse
on canal at the rate OF four miles an hour, is little
than l2 000lb. 1t is needless push this in
curry any farther; it is quite clear that goods can
never be transported on canal at rate exceeding
two two and half miles an hour. Let US see
COW what will be the effect Of an Increased rate oil
travelling on rail way. And here we shall arrive
at series Of conclusions dameti ically opposite to
those we have deduced for canals. The resistance
20 communication Of motion railway arises from
The friction and the resistance OF the air. For any
rate of travelling which Is likely to be adopted,
10, or IL miles an hour, The resistance arising from
The atmosphere is very trihing, compared with that
due 10 the friction. We shall therefore. altogether
neglect its consideration. The resistance DUE to the
friction is proportional only to the pressure. II is
entirely Independent Of the retocay This is he
9.rand circumstance which distinguishes rail way
from canal, and which gives the former such an
immense advantage over the latter. On canal, ny
increasing the velocity of the boat, we increase the
resistance 10 It's mOlloD at We RAPID rate by
increasing the velocity rail way, the resistance
Is not at all increased; it IS il any thing, rather
diminished AbstractiEg from consideration the
resistance of the air, the very force which impes a
body at lwc miles an hour, may, by very simple
contrvances, be made to mpel or twelve miles
40 hour. II we apply to the body to be moved on
rail way, force just equal to the resistance due
10 The friction. it will not move; it will be exactly
in state Of equilibrium. But the smallest increase
Of force will put in motion If this small increase
Of force be constantly acting force, like that due
steam, its motion will be continually accelerated
and would ultimately, become greater than any
assgnaoe limit. Here We see the advantage OF
steam power; animal power could never be so
applied as TO produce this effect, because, as the
velocity OF the vehicle increases, the draught of ami
nal power is diminished, becoming small indeed
when it reaches the velocity Of 10 or IL miles an
hour. When the vehicle has attained any proposed
velocity whether that velocity be generated in the
first instance by the continued action of the impel
ling torce or BY any other means. it is merely ne
cessary, in order that it should retain that velocity
that there should be an impeng force just suffi
cent to overcome the friction and the resistance to
the air Hence, on raiI 'cay, the expenditure OF
free due to a retocity Of ten on t,ceire miles an
honr, is rpry little more than hat due to retocita
Of tao mites IN hour. This is the grand nechani
cal advantage which rail road possesses over {