The convenience to the public I consider quite unquestionable. Mr. Hawkshaw's excellent notion may in fact be perfectly carried out. Every advantage in this respect that the advocates of the atmospheric system put forward, as to result from its introduction, may be actually realized by the LOCOMOTIVE CARRIAGES, which I consider it never can be by the atmospheric or vacuum pipe.

The only other point in which I have to examine the locomotive carriage, is its relative safety. In this respect it is, or may be made, more perfect than any railway mechanism hitherto suggested that has come under my notice. Its merits are in this respect summed up in Mr. Samuel's words, by stating that "it will be EASILY STARTED and EASILY STOPPED." Accidents to passengers usually happen by reason of the unwieldy nature of the trains, which it is impossible to start quickly, so as to get out of the way an impending collision, and impossible suddenly to stop, owing to the huge disconnected mass in motion; and again, when the locomotive train is suddenly stopped, as by the engine getting off the line, the collapse is productive of fearful mischief.

of

The theory of this part of the subject requires a moment's elucidation. It has been overlooked. It has been mistaken. It is, however, very simple. The law of the horizontal motion of bodies retarded by friction, is, that the space through which a body, endowed with a certain velocity, will pass, before being brought to rest, is equal to the quotient of the initial velocity squared, divided by the product of twice the coefficient of friction (adhesion) into the coefficient of

gravity. The space in question is absolutely independent of the mass (mechanically speaking) of the train, or of the body in motion. It depends essentially on the amount of the weight of the train brought to bear so as to increase the adhesion.

Thus, suppose a train composed of a locomotive engine weighing twenty tons, a tender weighing eight tons, and of ten carriages weighing each five and a half tons, to be going at thirty miles per hour, and requiring to be stopped as soon as possible, a brake would, in ordinary cases, be applied to the tender's four wheels, and to one carriage; or thirteen and a half tons of the eighty-three tons in motion would be used as a friction brake. The adhesion -the coefficient of friction-we shall still suppose to be one-seventh = 0.143. The minimum distance within which such a train would come to rest, is, by theoretical calculation, very nearly 420 yards, whereas, had it been possible to apply the brake to the whole weight in motion, that is, to all the wheelsto the locomotive, and to all the carriages-it would have come to rest after passing through a space of seventy yards. Were it even possible to apply the brake to the locomotive and tender, so as to make the whole of their weight available for friction, the train would stop after passing through a space of about 200 yards. The brake cannot safely be applied at once to such a mass as a locomotive train, and hence, practically, greater distances are required for bringing up a train than the theoretical calculation given.

For the locomotive carriages, the arrangement of

the framing is such, that the whole weight of the carriage can be brought to bear at once to produce friction; and therefore, from a velocity of thirty miles per hour, these carriages could be brought to rest in seventy yards; and even from a velocity of sixty miles per hour, the carriage could be brought to rest in a distance of 250 yards. To bring an ordinary locomotive train to rest from a speed of sixty miles per hour, would require the application of the brakes to the tender and one carriage over a space of 800 yards, or nearly half a mile.

The advantages of the small mass of the locomotive carriages are nearly as prominent, in reference to the facility of starting them with considerable speeds, as are those of their connectedness or uniqueness in reference to facility of stopping them.

These properties of the locomotive carriages, and of the trains that in any ordinary circumstances would be in motion under the system they will lead to, have (besides the comparatively great guarantee against collisions they give to this mode of conveyance) the advantage of allowing of many more stoppages at intermediate points on the line, without material loss of time. The facility of stopping and starting likewise gets over the difficulty of curves. The locomotive carriages may be stopped, or nearly so, and taken slowly round sharp curves, without any material loss of time. In short, the locomotive carriage seems to open up an avenir in railway travelling, far excelling in every essential to the convenience and economy of public traffic, the present locomotive engine system.

I

There may arise difficulties in the minds of railway-traffic managers, as to the manner of conducting traffic with frequent departures at various rates of speed; but the men who have brought the present system to work well will have, I believe, a light task in developing the locomotive carriage systems. therefore close here this attempt to lay before the public in general, and railway engineers and directors in particular, the advantages of locomotion by locomotive carriages, instead of the present expensive system of steam-tugs.

My friends will give me credit for having conscientiously investigated what I took in hand; and if I be mistaken in any calculation I have made, or in any notions I may have adopted, let my readers

believe of their Author that—

Non fumum ex fulgore sed ex fumo dare lucem cogitat....

APPENDIX.

No. I.

IN mentioning the name of Hancock in reference to the successful use of locomotive carriages on common roads, I mean not for an instant to deny the equal, if not greater, honour due to Mr. Goldsworthy Gurney, Sir Charles Dance, Colonel Macerone, and Mr. Squire.

A glance at the history of locomotion by locomotive carriages cannot fail to be interesting at this moment, confining the retrospect to within the period when locomotive carriages actually conveyed passengers on roads.

In 1825, a patent was granted to Mr. Goldsworthy Gurney for propelling carriages by steam on common turnpike roads. The novel and difficult nature of the mechanism presented numerous obstacles in practice, which required considerable time, and a succession of extensive trials and experiments, to over

come.

In 1826, Mr. Gurney's carriage "went up Highgate Hill, and to Edgeware, also to Stanmore, and went up Stanmore Hill and Brockley Hill, and against all these hills the wheels never slipped." This carriage ran to Barnet, and went up all the hills to Barnet in 1827, with only one wheel attached or fastened on to the axle; and was run for eighteen months experimentally in the neighbourhood of London. In 1829, "this carriage went to Bath, and over all the hills between Crawford Bridge and Bath, and returned, with only one wheel attached to the axle, an additional passenger carriage, taken in train, having broken in the first onset, and was not repaired until after its return.