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.”

J. S. Hodson, Printer, 15, Cross Street, Hatton Garden.