Bodies moving on levels at the under mentioned velocities,the motions of which are changed from horizontal to ascending, bymeans, either of angular or circular ascents. | Have moments, which (friction beingcounteracted) will cause them to rise to the under-mentionedheights above the level where those velocities were attained, letthe rate of rise, or angle of ascent, be what it may. | |
MILES PER HOUR. | FEET. | INCHES. |
3 | 0 | 3½ |
4 | 0 | 6⅜ |
5 | 0 | 10 |
6 | 1 | 2⅜ |
7 | 1 | 7⅝ |
8 | 2 | 1⅝ |
9 | 2 | 8½ |
10 | 3 | 4 |
11 | 4 | 0 |
12 | 4 | 9⅝ |
13 | 5 | 7¾ |
14 | 6 | 6⅝ |
15 | 7 | 6¼ |
16 | 8 | 6⅝ |
17 | 9 | 7⅞ |
18 | 10 | 9⅞ |
19 | 12 | 0⅝ |
20 | 13 | 4½ |
A velocity of six miles an hour being thus capable of giving momentum sufficient to enable any vehicle to surmount an ascent of above one foot in perpendicular height, let the angle of ascent or rate of rise, be what it might, it has been necessary only to lay out our turnpike-roads in alternate short levels, with sharp rises of one foot in height between them, similar to the line below, to render all our roads level, in point of effect, to every vehicle which went at the rate of six miles an hour; since, as the continued draught of the horse would overcome, neutralise, and (as relates to its counteractive effect) annihilate the friction of the wheels and axes during the ascent, the momentum imparted by that velocity would enable the vehicle of itself to rise up, and surmount the ascent, without any extra effort on the part of the horse: while, supposing that the practice of stage-coachmen were to be imitated, and the horses of these six-miles-an-hour vehicles pushed to a pace of twelve miles an hour for a few yards before the wheels actually touched these rises, so as to give the vehicle a velocity of 12 miles an hour at the moment of its beginning to ascend them, the momentum imparted by this velocity would carry the vehicle up four feet nine inches perpendicular, instead of one; so that the road might be laid out in alternate levels and rises of four feet.
It is true that, supposing this principle to be acted on, half the width of the road must be left in the usual manner, in order to enable waggons, which do not move faster than two or three miles an hour, to pass over it. But as the slow rate of two miles an hour will give momentum enough to admit of a rise of 1⅝ inches being surmounted, the principle might be taken some advantage of, even on the half of the road appropriated to waggons; since rises not exceeding 1½ inches each, could be surmounted by vehicles which did not move faster than two miles an hour.
However, leaving the waggon-half of the road to the usual arrangement, the advantage of, as it were, doing away with all hills and rises, and rendering all our roads level (in point of effect) to all vehicles travelling at the rate of six miles an hour, might have amply repaid the expense of this suggested alteration in the form of the roads, had the engineers under whose direction they were cut, but laid them out in that manner: while, supposing that a rate of 16 miles an hour could be attained by pushing the horse to a gallop just before reaching the ascent, the levels and rises might be laid out in gradations of eight feet each instead of four feet.
But let the heights of these proposed elevations be what they might, the advantage of (in effect) doing away with all hills and rises, and of rendering our roads level to us all over the kingdom would be attained; which might prove ample reward for varying the mere form of the roads; and would not, I think, have been unworthy the notice even of our omniscient engineers; notwithstanding that the way in, and degree to which they have neglected and slighted this law of motion, with respect to its application to railways as well as to turnpike-roads, proves them, one and all, to have been equally percipient of its advantages, as they were of the practicability of rapid conveyance on canals; and as they are of the merits of the method of transmission which the individual who has now the honour of addressing you is presumptuous enough to think deserving even of THEIR attention: omniscient as they deem themselves relative to it; and omnipotent as they have, hitherto, proved, with respect to its condemnation and rejection.
Should I, however, be fortunate enough to meet with any who will measure the competence of these gentlemen thus to condemn, by the following standards, I cannot but trust that my appeal from their decision will be favourably received.
The question, divested of technicalities, resolves itself into the three following considerations.
First, can we construct iron (or any other kind of) tunnels, such as would be requisite for the operation of the principle? Secondly, can we construct air-pumps large enough to exhaust from the said tunnels with the necessary rapidity? And, thirdly, can we make steam-engines powerful enough to work these air-pumps?
Now as there is no one who denies that we have the power of making tunnels of any size, not exceeding (say) twelve feet in diameter, nor that we can form the separate segments, or pieces, in which such tunnels might be cast, into cylindrical “lengths,” of from ten to fifteen feet each, so as to lay them down and connect them as (suppose for the present) gas mains are laid down and united—as no one denies this, the second question, relating to the air-pumps, is the first to be replied to.
In 1827 there were, in Great Britain, 284 smelting furnaces; the quantity of iron made during that year by which, was 690,000 tons.