AS the first evidence that “the observations which will be found in the
course of this letter relative to the effects of momentum, are not of
such recent origin in my mind, as Mr. Badnall states his idea relative to
the undulatory railway to have been in his,” I observe, that in the
specification of my patent, after declining to level for the course of my
tunnel by cutting through hills or filling up vallies, as is done for
railways, I state, that I carry it up and down them (provided they are
not precipitously abrupt) for the reason, that “the momentum it (the
carriage) may thus acquire, will be advantageous in other ways than
merely carrying itself forward.”
Secondly. The last sentence of the paragraph commencing “Tenthly,” in
the Report of the Russian Engineer Officer, implies that that gentleman
had understood what I have stated relative to this effect of momentum,
from my communications to him.
Thirdly. The plan and section of the Brighton and Shoreham Pneumatic
Railway, which I deposited in the County Court in 1827, and in Parliament
at the beginning of the session of 1828, prove that the whole rise from
Shoreham Harbour to the spot on the _top_ of the hill _above_ Brighton
(old) Church, where I intended said Pneumatic Railway should terminate,
was (I forget the exact amount, but) about 180 feet: of which rise, about
150 feet took place in the last half mile; giving a rate of about 1 in
18: up which rise I looked to momentum, as the _principal_ means of
getting the 100,000 tons of goods I calculated on carrying between those
places.
Fourthly. In my letter to Mr. Ricardo, in answer to his pamphlet against
me, I observe, that after totally omitting to take into consideration the
important effect which momentum (_as well of the air itself as of the
vehicle_) would have in modifying the motion, and preventing the stoppage
of the carriage, in the way you describe at page 21, you exclaim, “This
then, is a true philosophical explanation, of what will take place in the
action of a carriage impelled by atmospheric pressure!”
Against such philosophy as this I protest, in justice both to myself and
the public. As the basis of lectures delivered at your Mechanics’
Institution, where
—“words of learned length and thundering sound
Amaze the _operatives_ rang’d around,”
it may have sufficed. But when held up as a criterion by which the
public mind is to take its tone for my condemnation, I am compelled to
pronounce it philosophy of which its author ought to be ashamed.
These evidences being all of dates several years anterior to the period
when Mr. Badnall states the idea of his “Undulating Railway” first
occurred to him, I shall be liable to no charge of proposing to avail
myself of momentum _in consequence_ of his having proposed “_Undulating_
Railways.”
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J. S. HODSON, Printer, 15, Cross Street, Hatton Garden.