It is now four years ago since the locomotive engine competition took place on the Liverpool and Manchester Railway. In all probability no proprietor of the Kensington Canal happened to be present at that contest; yet is it equally probable that all were as fully convinced of the fact from the accounts which appeared in the newspapers, as if you had seen it. Now though I cannot give the conviction arising from the evidence of your senses, yet can I give stronger evidence than the public vehicles of intelligence gave as to that competition, by referring you to the public authorities and records of Brighton, to know whether I did not carry an appointed number of its inhabitants to and fro, as the locomotive engines went during that competition; “when,” says Mr. Treasurer Booth, in his “Account of the Liverpool and Manchester Railway,”—“the prescribed distance, it should be understood, was, owing to the circumstances of the railway, obliged to be accomplished, by moving backwards and forward on a level plane of one mile and three quarters in length.” I did not, it is true, carry those gentlemen so far as those engines went. Nor, indeed, was there any occasion for it. Had it been necessary, they could have continued riding to and fro in my tunnel, as long as the locomotives ran to and fro on the railway. But, as when they had satisfied themselves that there was no trickery in the motion of the carriage, and that it was really moved by the air, they had, then, seen all that it was necessary to see, to convince them that a longer tunnel would enable me to move a carriage equally far, as a longer railway would have admitted of the locomotive engines going, they gave over riding, “because,” as the Editor of the Brighton Herald says, in the extract which I have quoted from that paper, “because they became so convinced that the invisible and intangible medium we breathe, might be rendered a safe and expeditious means of getting us from one place to another, as to be tired of riding.”
Were it necessary for your interest that a gas-pipe should be laid throughout the line you propose, your inquiry of the engineer you might employ would be, not whether the gas would pass through such a length of pipe, because you know that to have been long established, and to be every day acted upon, but what would be the expense of it; that is, it would be a money question, not a question of practicability.
The tunnel I constructed at Brighton was nearly eight feet in diameter, while the air-pumps I adapted to it were large enough to make an artificial wind blow through it at the rate of ten miles an hour. And doubling, tripling, quadrupling, &c. &c. the size, or number of the pumps, would have doubled, tripled, &c. &c. the rate at which this wind blew.
A common size for gas mains is eight inches. Were it propounded to you—“Can a mouse run through a rat-hole, let that bole be as long as it may?” your answer would not be dubious. Why, then, if it be proved, that we can, with pneumatic apparatus of an almost infinitely less efficient nature than that which I purpose using, make air move through smaller pipes five, fifteen, or even fifty miles long, [72] should any doubt be entertained whether air-pumps will cause it to move through one of eight feet in diameter; more particularly, when it is well known, that the larger the pipe the less the proportionate friction; and when your line will be little more than two miles long.
The pressure by which the gas is driven through the pipes of the work I know the most of, is equal to an ounce and a half per square inch. A similar pressure on the carriage in my tunnel would have moved above one hundred tons. The length of your line would be only about eighty times longer than the tunnel I constructed; and as the area of your tunnel would be nearly 150 times larger than the eight-inch mains through which the gas is carried many times farther than the length of your line, there need be no more question as to whether, or not, the principle will act throughout your line, merely because it is eighty times longer than my tunnel, than there is whether gas would pass through eighty lengths of gas-pipe.
And as the joints which connect the different “lengths” of gas-pipes can easily be made air-tight, so could the “lengths” and joints of the tunnel. “Under the trivial degree of exhaustion which will be necessary,” says the Report of the Russian Engineer Officer, “rendering the tunnel sufficiently air-tight will be far less difficult than is at first supposed. Indeed, I see so many different ways of doing it,” continues the Report, “that I am satisfied it would not, in practice, prove more difficult than, nor, indeed, so difficult as, causing some canals I have seen, to retain the water let into them.” Following up the illustration which this gentleman thus gives, I beg to assure you I will guarantee that the tunnel shall not leak, or let air improperly in, so much as I see the basin of your canal leaks water out.
Adverse as were the original circumstances of the great father of canal navigation in England, yet did he put to signal shame the opposition and predictions of the engineers who proclaimed him a madman for pretending that it was possible to carry a canal over a navigable river. Ten thousand times more mad as the engineers of the present day proclaim me, and a hundred thousand times more absurd and “impossible” as they have pronounced my proposition to be, yet, owing to having in my favour (what Brindsley had not in his) the circumstance of my principle having been tried, I am enabled to oppose to their ridicule and sneers the FACT that I have proved it on a scale, which, as relates to size, was fully, and in every particular practical; while it was less than practical in point of length, only because no individual could do that which it requires a public company and an act of parliament to do, that is, lay it down between places for actual trade.
Short, however, as it was, yet was it many times longer than the pipes through which gas was first carried, to prove the practicability of lighting our streets with that illuminator: while its length was great enough to be equally conclusive, as the movement of the first steam-vessel built by the introducer of steam-navigation.
“When,” says Fulton, “I was building my first steam-boat at New York, the project was viewed by the public either with indifference or with contempt, as a visionary scheme. My friends, indeed, were civil, but they were shy. They listened with patience to my explanations; but with a settled cast of incredulity on their countenances. I felt the full force of the lamentation of the poet:
‘Truths would you teach, to save a sinking land,
All fear, none aid you, and few understand.’