seen.

THE ATMOSPHERIC RAILWAY.

From the British and Foreign Review.

THIS is the most complete view of this wonderful application of our common air to purposes of locomotion, which we have yet It will be read with interest, and we hope will lead to an experiment in our own country. One great advantage of this mode of conveyance, not mentioned in any reports, will be exemption of eyes from cinders, and of dresses, barns, etc., from burning.—ED. 1. Report of Lieut.-Colonel Sir Frederick Smith and Professor Barlow, to the Right Honorable the Earl of Ripon, President of the Board of Trade, on the Atmospheric Railway. Presented to Parliament by command of Her Majesty. London, 1842.

years, several thousand miles of railway have been laid down in the British empire; and above sixty millions sterling had in 1841 been embarked in railway speculation; independent of this, is the still greater projected extent of its adoption on the continent. When we consider all the difficulties to be overcome, the immense amount of labor to be encountered, and the enormous capital that has been so easily found and so readily embarked in this gigantic enterprise, we find cause for admiration, not less at the power, skill, and industhis Herculean task, than at the apparently try which have been brought to bear upon

limitless resources of our national wealth.

nius. We are not content to look back

The invention and the successful application of such a power might appear suffi2. Rapport, addressé à M. le Ministre des cient for one age, were it not that the charTravaux Publics, sur le nouveau mode acteristic of power is to multiply itself, and de locomotion, dit Système Atmosphé-incitement to fresh efforts of inventive gethat every new discovery proves only the rique. Par M. Edmond Teisserenc. Paris, 1843. 3. Report on the Railroad constructed from upon what has been achieved, but press Kingstown to Dalkey, upon the Atmospheric System, and upon the Application of this System to Railroads in general. By M. Mallet. London: John Weale, 1844. 4. A Treatise on the Adaptation of Atmospheric Pressure to the purposes of Locomotion on Railways. By J. D. A. Samuda. London: John Weale, 1841.

continually forward to what we are capable of accomplishing: new means beget fresh wants, and these again are the stimulus to those whose task it is to provide for them.

The history of the discovery which we shall sketch in the present article, presents an interesting chapter in the annals of invention, apart from its vast importance in reference to practical results; and we deem a subject of such universal concernment 5. The Atmospheric Railway. A Letter this view we shall, in the first place, relate to be deserving of an historic record. With to the Right Hon. the Earl of Ripon, briefly the origin and progress of the inPresident of the Board of Trade, etc.vention of the Atmospheric Railway, and By James Pim, Jun., M.R.I.A. Lonshall reserve our remarks on its application

don, 1841. 6. Observations on the Report of Lieut. to the conclusion of this article. Colonel Sir Frederick Smith, R.E, and Professor Barlow, on the Atmospheric Railway. By T. F. Bergin, M.R.I.A. London, 1842.

AMONGST the inventions which within the last twenty years have rapidly followed one another, in the application of steam power to works of public utility, the most important is the Railway. Scarcely fifteen years have elapsed, since the practicability

of this means of locomotion was untested even by experiment; and the astonishing rapidity with which, as soon as this point was ascertained, the invention was brought into general use, is itself a criterion of its vast importance. During the last twelve

The Liverpool and Manchester line was opened to the public September 15, 1830.

air in land-carriage occurred to a gentleThe first idea of employing the power of ventor of the first power-loom,) in 1805. man at Manchester, Mr. Taylor, (the in

In conversation with two friends, Mr. Duckworth and Mr. Clegg, the subject was discussed; and, although these gentlemen were all of opinion that the idea was capa ble of being realized, the means of accomplishing their object was so surrounded with difficulties, that the subject was ultimately dropped without any steps being taken or experiments made. The plan proposed was in principle the same as that which is now in successful operation in Ireland,—namely, the application of atmo

* Mr. Papin originally suggested employing atmospheric pressure against a vacuum, but not for these purposes.

"When the carriage is to go through the canal, from the engine, the air must be forced into the canal behind it; but when it is to go the contrary way, the same engine is to draw the air out of the canal, and rarefy the air before the carriage, that the atmospheric air may press into the canal behind the carriage, and drive it the contrary way."-Page 15.

The next suggestion of Mr. Medhurst was as follows:

munication between the inside and the outside

spheric pressure obtained by the exhaust-wheels of the carriage to run upon; and the ing power of the air-pump. Mr. Taylor's carriage must be nearly of the size and form scheme only extended to the conveyance of of the canal, so as to prevent any considerable letters and despatches; he suggested that a is forced into the mouth of the canal, behind quantity of air from passing by it. If the air tube, large enough to contain a parcel, the carriage, by an engine of sufficient power, should be laid down from one town to an- it will be driven forward by the pressure of the other at these places a stationary steam-air against it; and if the air is continually engine should be erected, which should ex-driven in, the pressure against the carriage, haust the tube. The parcels being placed and consequently its motion, will be continually maintained."-Page 3. in the tube at one end, and the latter exhausted by an engine at the other, the pressure of the air would carry the contents of the tube along with immense velocity; at each station or town the letters and parcels intended for that district would be taken out, and the rest forwarded to their destination. This ingenious suggestion was never published; we believe that it has remained to the present time wholly unknown: its interest will be seen as we proceed. In 1810, Mr. George Medhurst, an engi"It is practicable, upon the same principle, neer in London, published a pamphlet, in to form a tube so as to leave a continual comwhich he proposed a new method of con- of it, without suffering any part of the impelveying goods and letters by air;" and in ling air to escape; and by this means to impel a 1812 he published his calculations and re- carriage along upon an iron road, in the open marks on the practicability of the scheme. air, with equal velocity, and in a great degree "These publications," he says, "met with possessing the same advantages as in passing that indifference and contempt which usual-withinside of the tube, with the additional satly attend all attempts to deviate so widely and in view of the country. If a round iron isfaction to passengers of being unconfined, from established customs." His sugges-tube, 24 inches in diameter, be made, with an tions led however to no attempt to test their opening of two inches wide in the circumfercorrectness; but in 1827 Mr. Medhurstence, and a flanch 6 or 8 inches deep on each printed another pamphlet, in which the side of the opening, it will leave a channel beauthor suggests four applications of the tween the flanches, and an opening into the principle of atmospheric pressure to purpotube. If such a tube is laid all along upon the ses of travelling, which we will describe in ground, with the iron channel immersed in a channel of water, and a piston or box made his own words. The passages we select to fit it loosely, and pass through it upon wheels contain the whole account of what he pur- or rollers, this box, driven through the tube by posed to accomplish, the rest of the pam-the air forced into it, may give motion to a carphlet being filled with calculations and de- riage without, by a communication through the tails of management, which it is unneces-channel and the water. No air can pass out of the tube while the channel is immersed in sary to quote. water, unless the air is of such density as to "In order to apply this principle to the pur-force the water out of the channel, and then pose of conveying goods and passengers from the air will follow it and escape; but there is place to place, a hollow tube or archway must an opening made for a bar of iron to pass from be constructed the whole distance, of iron, brick, the running box, in the interior of the tube..... timber, or any material that will confine the to which a rod or crank may be brought from air, and of such dimensions as to admit a four-the carriage in the open air, and from that rewheeled carriage to run through it, capable of ceive its motion." carrying passengers, and of strength and capacity for large and heavy goods. The tube or aërial canal must be made air-tight, and of the same form and dimensions throughout, having a pair of cast-iron or stone wheel tracks securely laid all along the bottom, for the

A third plan was the following:

"A plan to combine the two modes together, that the goods may be conveyed within the canal, and a communication made from the inside to the outside of it, so that a carriage may *It was entitled "A new system of inland be impelled in the open air, to carry passenconveyance for goods and passengers, capable of gers, would be an improvement desirable and being applied and extended throughout the coun-practicable. It must be effected without the try, and of conveying all kinds of goods, cattle, and passengers," etc.

aid of water, that it may rise and fall as the land lies; and it must give a continual impulse

to the outside carriage, without suffering the impelling air to escape. For this purpose there must be some machinery which will diminish the simplicity, make it more expensive, and more liable to be disordered, unless executed in the most substantial and perfect manner; but by skill, by experience, and sound workmanship, it may be accomplished in various ways."

the subject for a patent. A model of this railway was exhibited at Brighton, but this was the extent of its application.

We shall briefly notice a claim put forward by Mr. Pinkus to be the inventor of a pneumatic railway. He obtained a patent March 1st, 1834, for a contrivance precisely similar to that which Medhurst had published seven years before, excepting that he proposed to use a rope for the continuous valve, and substituted a cylinder for a square tube, which he describes as follows:

:

"A flexible cord lies in the groove at the top of the cylinder, for the purpose of closing the longitudinal aperture; this cord is to be of the same length as the pneumatic railway, and to fit tightly into the groove or channel."

Mr. Medhurst suggested a fourth idea:"The same principle and the same form, may be advantageously applied to convey goods and passengers in the open air, upon a common road, at the same rate of a mile in a minute, or sixty miles per hour; and without any obstruction, except, at times, contrary winds, which may retard its progress, and heavy snow, which may obstructit. If a square iron tube be formed, two feet on each side, four feet in area, with three sides, and one half of the top, of cast iron, the other half of the top made of plate iron or copper, to lift up and shut down in a groove in the cast-iron semi-top plate, as before described; and if a strong and light "The method of carrying it into practice box or frame be made to run upon wheels consists in a method or in methods of constructwithin the tube, and an iron arm made to passing the pneumatic valve and the valvular cord, out, through the opening made by lifting up the plate, as before described, this arm may give motion to a carriage in the open air, and upon the common road, without any railway, if the pressure within the tube is made strong enough for the purpose."

The failure of this scheme was shown by the fact, that Mr. Pinkus took out a new patent in 1836, in which he says,—

and in the manner of using the same, one of which methods hereinafter described, I design to substitute for and in lieu of the valve and cord described in the specification of my said former patent."

It is unnecessary to describe the specifiThis pamphlet is now simply an interest- cation of this contrivance, which proved a ing historical document: the suggestions second failure; but we must note that it in of its author led at the time to no practical no way anticipated or resembled the subseresult, because, although he understood the quent invention of Mr. Clegg. The diffiprinciple, the point upon which its applica- culty had still to be conquered, and no apbility entirely depended was unattained:proach to this had been made, since Mr. the difficulty was, to find the means of rendering a tube sufficiently air-tight, and at the same time of allowing a piston, which should connect the motive power within the tube with the bodies to be propelled on its outside, to pass freely along an opening in

this tube.

Previously, however, to the appearance of Mr. Medhurst's second tract, a patent was taken out by Mr. Vallance in 1824 for a plan of locomotion by atmospheric pressure. This was merely a modification of Mr. Medhurst's first scheme of exhausting a tunnel large enough to contain a train of carriages a stationary engine was to be erected at one end of this tunnel, which, it was supposed, would create a sufficient vacuum for the pressure of the air acting on a piston attached to the first carriage to impel the whole train forward. It is astonishing that a plan, for many reasons so palpably impracticable, engaged the attention of any man of sense, or was made

Medhurst first suggested the idea of making a continuous communication between the inside of the tube and the carriage withoutside, sufficiently air-tight for the object required. On the 3d of January, 1839, Mr. Clegg took out his patent, which we shall presently describe, and on the third of August following Mr. Pinkus took out a third patent, in which he introduces a valve in every respect similar to that of Mr. Clegg, and further proposes to seal it with a composition to be alternately fluid and solid, as described in Mr. Clegg's patent, with the only difference that the composition was to be melted by a galvanic wire instead of a heater. This patent was enrolled eight months after the publication of Mr. Clegg's specification.

All the attempts hitherto made to overcome the difficulty we have mentioned had failed, until the invention of Mr. Clegg effected this, in a manner which, from subsequent experiments, removes any doubt as to the

practicability of the atmospheric railway, coulter. In this position, if part of the air be and opens a new prospect of advantages, the extent of which cannot at present be calculated. The principal feature of this invention consists in "a method of constructing and working valves in combination with machinery," to be applied to railways or other purposes, by a line of partially exhausted pipes, for the purpose of obtaining a direct tractive force to move weights, either on the railway or otherwise." The following extract from Mr Clegg's specification explains this:

withdrawn from that length of pipe in front of the piston by an air-pump, worked from a stationary engine or by other mechanical means, placed at a suitable distance, a certain amount of pressure on the back of the piston (being the locomotive force) will take place, proportioned to the power employed. In practice, and to work economically, it will be sufficient to produce an exhaustion of air in the pipe, equal to causing a pressure from the atmosphere, upon or behind the travelling piston, of 8 lbs. per square inch, which is only about onehalf the pressure due to a vacuum. Supposing the main pipe to be of 18 inches internal "My improvements consist in a method of diameter, it will receive a piston of 254 superconstructing and working valves in combina- ficial inches area, on which, with the above tion with machinery. These valves work on a pressure, a tractive force of 2,032 lbs. is consehinge of leather, or other flexible material, quently obtained; and this is capable of prowhich is practically air-tight (similar to the pelling a train weighing 45 tons (or eight to valves commonly used in air-pumps), the ex-nine loaded carriages), at the rate of 30 miles tremity or edge of these valves is caused to fall into a trough containing a composition of bees' wax and tallow, or bees' wax and oil, or any substance or composition of substances which is solid at the temperature of the atmosphere, and becomes fluid when heated a few degrees above it. After the valve is closed, and its extremity is laying in the trough, the tallow is heated sufficiently to seal up or cement together the fracture round the edge or edges of the valve, which the previous opening of the valve had caused; and then the heat being removed, the tallow again becomes hard, and forms an air-tight joint or cement between the extremity of the valve and the trough. When it is requisite to open the valve, it is done by lifting it out of the tallow, with or without the application of heat, and the before named process of sealing it, or rendering it air-tight, is repeated every time it is closed. This combination of valves, with machinery, is made in the application of these valves to railways, or other purposes, by a line of partially exhausted pipes for the purpose of obtaining a direct tractive force to move weights, either on the railway or otherwise."

In a pamphlet printed in 1841, Mr. Pim, the treasurer of the Dublin Railway Company, addressed a letter to the Earl of Ripon, then President of the Board of Trade, on the subject of the atmospheric railway. From this work we shall extract a simple description of the invention.

an hour, up an acclivity of 1 in 100, or 53 feet per mile. The iron coulter being fixed to the travelling piston within the pipe, and also to the leading carriage of the train, connects them together, moving through an aperture formed in the top, and along the whole length of the pipe; while one set of vertical rollers attached to the piston rod, at some little distance behind the piston, progressively lift up for the space of a few feet, and another set of rollers attached to the carriage close down again, a portion of a continuous flexible valve or flap, of peculiar construction, covering the aperture; and it is the very simple, ingenious, and efficient mode of successively opening, and closing down and hermetically sealing this valve, as each train advances and moves on, that constitutes the merit of the invention, and the foundation of the patent; the operation consisting first, in opening the valve to admit the free admission of the external air, to press on the back of the piston, and produce motion; and then in effectually closing down and sealing the valve again, so as to leave the pipe in a fit state to receive the travelling piston of the next train, and ready to be again exhausted of its air. Stationary engines of sufficient power, proportioned to the amount of traffic and speed required, would, in practice, be placed at intervals of about three miles apart, and be arranged to work the railway to that length, alternately on either side of their position, as might be required."-Pages 6-8.

The means of stopping a train and passing from one section of pipe to another are as follows:

"On this system of working railways, the moving power is communicated to the trains by means of a continuous pipe or main, of suit- "When it becomes necessary to stop or reable diameter, laid in the middle of the track, tard the carriages, in addition to the use of a and supported by the same cross-sleepers to common break, a valve in the travelling piston which the chairs and rails are attached. The may be opened by the guard or conductor of internal surface of the pipe being properly the train, whereby, the external air being adprepared by a coating of tallow, a travelling mitted in advance of the piston into the expiston made air-tight by leather packing, is in-hausted portion of the pipe, the propelling troduced therein, and is connected to the lead- power is at once destroyed. The separating ing carriage of each train by an iron plate or valves, in the main or pipe between each sec