Drawing on Cloth.-A new method of drawing on cotton and linen cloth has lately been invented by Mr. John Buck, of 12, Parker-street, Westmin. ster, which possesses, as far as regards the portability and durableness of the material, a great superiority over every other yet devised. The cloth is first prepared by rubbing into it an adhesive composition, which unites the threads, and makes it as easy to draw upon as paper; and after the drawing has been made, it is done over with a "thin pellucid liquid," or varnish. It might be supposed that cloth thus treated would be stiff and liable to crack; but, on the contrary, it admits of being folded of any shape or size, with the greatest ease, and without injury. A whole estate, or township, as the inventor observes, may, by this means, be introduced into a landagent's pocket-book."

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New Boiler.-Messrs. Petherick and West, of the Lanescot Mine, Cornwall, have invented and brought into use a boiler of a new construction, which is stated, in the last Annual Report of the Cornwall Polytechnic Society, to effect such an economy in the consumption of fuel, as to raise the duty performed by an engine to between ninety and a hundred millions of pounds! In Watt's time nineteen millions was considered prodigious. The improvement consists principally in having a horizontal cylindrical tube enclosed within the tube which contains the fire. Water is supplied to this inner tube from the feed pump; and the steam and heated air pass from it to the boiler, whence it is conveyed to the steam-pipe.

Berlin Iron Castings rivalled.-At the last an nual exhibition (at Falmouth) of the Cornwall Polytechnic Society, the first prize in the Fine Arts was awarded to Mr. Nicholas Harvey, of Hayle, for some miniature statues cast in iron, which were pronounced by Mr. Davies Gilbert, the Vicepatron of the Society (a good judge), to be equal to the best productions of the Berlin school..

Col. Macerone has sent us a note in reference to our review of his "Expositions and Illustrations," in which he says "I do not know exactly what to say, until I see whether you publish or not my brief reply to H.'s note in No. 607, which reply of mine you announce the receipt of in No. 608, and so I expected to see it in 609 or 610, where it is not! I should also like to know whether you think proper to identify yourself with your correspondent H., and mean to say that you and he are one and the same person., I am induced most respectfully to ask this question, because among the inpumerable mistakes in your oration, there is one of personal identity. You are pleased to take to your self expressions which, at pp. 93 and 101 of my pamphlet, I clearly and nominatively apply to your correspondents H, Verax, &c." We have, in answer, to inform Col. M., that H. and the Editor of the Mechanics' Magazine are not one and the same person; and that we do not intend publishing his "brief reply" to H.'s note, because the whole, of the matter in dispute between Col. M. and H. has been already disposed of by the extracts which we gave from Col. M.'s last pamphlet. The of fensive expressions, which we are said to have erroneously taken to ourselves, were, these:"Had I stopped short for want of coke, what would have been the cry or yell of the writers in the Mechanics' Magazine, and other of my, inveterate persecutors."-p. 93-"A periodical work, certain writers in which have all along evinced a most unaccountable, wanton, and ferocious disposition to calumniate and injure me."-p. 101. What else could we infer from such expressions as these, but that they were intended to apply to the Editor as well as to his correspondents? The Editor has, besides, no wish, and sees no occasion to wish, to separate himself from his correspondents on the

present occasion. He can see no material difference between an Editor's being personally guilty of calumny and persecution, and allowing his columns to be made use of for such purposes by others; and he must, in justice to himself as well as to his correspondents H. and Verax, and to the general character of his work, positively deny that any thing has ever appeared in its pages to warrant Col. M. in ascribing any other than that best of motives-a love of truth-to" the writers in the Mechanics' Magazine."

Halley's Comet.-A letter from Vienna announces that M. Littrow, director of the Observatory in that city, has received from the celebrated English astronoiner, Herschell, now residing at the Cape of Good Hope, the remarkable intelligence that Halley's comet, of which so much has been said, and which is positively expected in August this year, will not be visible, because it has long since changed the direction of its course, and now revolves in a different orbit. A report by our astro nomers, on this important subject, it is expected, Dutch will soon be published. Dutch Paper. fudge!

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Black Lead Pencils. -A M. Fichlemberg, of Paris, has invented a combination, which is said to possess all the desirable qualities of the pure plumbago of Cumberland.

Claims of Music.-The strictures of "Cui Bono," on the academic honours obtainable by professors of music at Oxford and Cambridge, sinack of an ultra-utilitarianism, which has not, we hope, many followers. Is he aware that Haydn was, for his music alone, elected a member of the French 10 stitute that most scientific and (probably) most universally respected of all learned institutions?

The Pueumatic Railway shall have full justice done to it in our next.

Mr. Clark's address is, 7, Nelson-terrace, Cityroad.

Mr. Beams has our best thanks. He will find the articles alluded to in Nos. 162, 167, 178, 179, 195, and 201.

Communications received from Mr.. Woodhouse -Mr. Baddeley-Mr. Laudale-Mr. Andrews.B. D. Z.-Amicus-E. E.-C.

The Supplement to our last. Volume, containing Titles, Index, &c., with a Portrait, on Steel, of Samuel Clegg, Esq., C. E., is now published, Price 6d.; also the Volume complete, in boards, Price 8s. 6d.

Our Publisher will give double price for copies of Nos. 236, 237, 238, 239, 256, 258, and One Shilling and Sixpence each for copies of the Supplement to Vol. X.

Patents taken out with economy and despatch; Specifications prepared or revised; Ca veats entered; and generally every Branch of Patent Business, promptly transacted. Drawings of Machinery also executed by skilful assistants, on the shortest notice..

LONDON: Published by J. CUNNINGHAM, at the Mechanics Magazine Office, No. 6, Peterborough-court, between 135 and 136, Fleet-street. Agent for the American Edition, Mr. O. RICH, 12, Red Lion-square. Sold by G. G. BENNIS, 55, Rue Neuve, Saint Augustin, Paris." CUNNINGHAM and SALMON, Printers, Fleet-street.

THE PNEUMATIC RAILWAY. A model, of what is called a " Pneumatic Railway," for which Mr. Henry Pinkus has taken out a patent, is now . exhibiting in Wigmore street; and a prospectus is in circulation of a “National Pneumatic Railway Association," to promote the adoption, on " all the railroads in England," of the system of transport of which this model is an exemplification. Copies are also handed about of " Opinions given by Dr. Lardner and Professor Faraday in favour of the system; and on the strength of these opinions very considerable sums are stated to have been sub

scribed to the projected "Association." We shall first lay before our readers as much of the prospectus as relates to the scientific merits of the project, and then the " Opinions" of Messrs. Faraday and Lardner entire; after which we shall add something in the way of an opinion of

"The invention, which is the basis of the improvement now submitted to the public, consists in the means of applying the elastic and forcing power of the atmosphere, obtained by rarefaction, within a hollow cylinder, of from thirty to forty inches in diameter, to carriages and cars running upon rails on its outer surface ;-the action being produced and transferred by means of pneumatic machinery, worked by sufficiently powerful fixed or local steam-engines.

Steam-power, used as a first mover, admits of no application so economical as that by means of fixed engines; and thus motive power will be obtained at one quarter the expense of that yielded by the locomotiveengine. The fixed engine gives also the advantage which the locomotive does not possess, that the intensity of its force can be greatly varied to suit the exigencies of the road; and thus it may be rendered available according to the nature of the slope or steepness of the acclivity to be overcome, the weight to be moved, and the degree of

rapidity required. Unlike that of the locomotive-engine, the power of the fixed engine is, by the improved system, communicated with no indirect expenditure to the load or train of carriages; whilst the power of the locomotive is first applied to bear along its own ponderous bulk-which is of about 10 tons weight, or fully one-fourth of its usual load -and, as before remarked, it destroys both railway and engine by its violent action and concussive force.

It

"The power of surmounting acclivities renders the most direct lines of communication available, and thus shortens the distances between places, and avoids the necessity of circuitous routes in search of levels. Moreover, the improved system of railway permits of roads being laid through a marsh as well as over a common or down, and with no greater expense; thus affording the means, in many cases, of avoiding the annoyance, inconvenience, and expense of running roads through parks, and over arable lands. may be remarked, too, that the great expense involved in the formation and construction of a railroad upon the common system, is totally sunk in cutting down, or in tunneling through hills, and in building across, or embanking over valleys; whereas the main expense involved in the formation of a road on the improved system, is in common iron castings, which being almost indestructible, and possessing an intrinsic value, little or no loss can accrue upon them.

"Not only does the improved system present a firmer construction of the railway, and a highly economical application of power, but it affords also greater protection to life and property, in the security of the carriages and cars for the conveyance of passengers and goods; since these are so placed upon the rails, and so connected with the railway itself, that they cannot, by any possibility, be thrown off or overturned. In consequence of this advantage, whatever objection may exist in the public mind to travelling upon railways, because of the danger connected with the common system, will be entirely removed, and a great improvement may be confidently calculated upon in the important item of passenger traffic.

"When it is considered that by the improved system a line of road may be formed and constructed, for, at the most, two-thirds, and in some cases, for one-half the expense involved by the common system; and that such a railway can be maintained and worked with far greater speed, and infinitely greater safety, for three-fourths less than the common system costs; and that therefore passengers and goods may be conveyed at one-half the price which the common system demands, and then yield a far greater profit, competition

with the Association will be wholly out of the question.

"As any degree of speed can be obtained by the improved system with the most perfect safety, and without the disadvantage, not to say danger, arising from great velocity on the common method, a single line on the new system can be made, by the reciprocating plan proposed, to effect as much transit as can be effected by the use of a double line on the former, while the cost will thereby be lessened nearly one-half. Hence communications that may not warrant the expense of a double line of railway, may be advantageously occupied with a single line; numberless lines are in this manner open to the application of the new system, which the common method will not permit of being attempted.

"As the invention affords the means of applying the power to the common railway, the proprietors of such must soon be found anxious to avail themselves of its advantages; and thus all the railroads in the country may soon become tributary to the Association, while the interests of the various concerns themselves will be materially improved by its adoption."

Prefixed to the prospectus there are two views, of which those on the frout page of our present Number are reduced copies; Fig. 1, representing the Pneumatic Railway, as it would appear in actual operation; and Fig. 2, a sectional view of the Railway Cylinder, exhibiting the internal arrangement.

Opinion of Dr. Lardner.

I have read the specification of the patent for the Pneumatic Railway and the accompanying papers, and have also examined the drawings and models which have been submitted to me by Mr. Hocking.*

Two methods have been heretofore employed for rendering steam power available in transport upon railways; one by causing a travelling or locomotive engine to move with the load which it draws, the other by constructing, at intervals of about a mile and a half, stationary steam-engines, the power of which is transmitted to the load by a rope carried along the road upon rollers or sheaves placed between the rails. The train being attached to this rope is drawn by the power of the engines from station to station. The object of the Pneumatic Railway is to substitute for the rope a partially exhausted tunnel, to employ the fixed steam-engines to work air-pumps by which a rarefaction of the

Professional Director of the undertaking.ED. M. M.

tunnel shall be maintained, and to cause the trains to be tracked upon the railway by connecting them with a diaphragm or piston placed in the interior of the tunnel, so as to have that part of the tunnel in advance of the piston rarefied by the engines, while that part behind the piston is open to the atmosphere. An effective impelling power is thus obtained equivalent to the difference between the pressure of the atmosphere on one side of the diaphragm, and of the rarefied air on the other. !!!

Of the practicability of this project, I think there can be no doubt. The working of large air-pumps, by an adequate moving power, and the rarefaction of air in tubes or tunnels by such means is not a new idea. It was suggested by Papin in the latter end of the seventeenth century, and was even pointed out by him as a means of transferring power to a distance, without the loss by friction and other causes consequent upon the use of ropes, or other ordinary means of transmitting force. It is, in fact, a well understood principle in physics, that whatever moving force be expended in producing the rarefaction of air in a cylinder or tunnel, must necessarily be followed by a corresponding force on the other side of a diaphragm moving air-tight in that tunnel, and exposed to the free action of the atmospheric pressure. In the present case, supposing the structure of the valvular cord and the pneumatic piston to be perfect, the opposite side of the diaphragm will always be pressed by an effective impelling force, the amount of which may be calculated upon these principles. It will, of course, be perceived that no original moving power is obtained from the tunnel, or from the rarefied air; the rarefaction gives back the power expended by the stationary engines, and nothing more; and the tunnel must therefore be regarded merely as a substitute for the ropes in the common method of working railways by stationary engines. But it is evidently attended with several advantages in comparison with the latter. A very large proportion of the moving power of stationary engines worked by ropes is intercepted by the resistance from the weight and friction of the ropes, sheaves, barrels, drums, &c. All such waste of power is removed by the pneumatic tunnel.

The original expense of ropes, and their wear and tear, would be likewise saved. Some notion of the extent of this saving may be collected from the following facts: when the Liverpool and Manchester Railway was about to be brought into operation, a question arose as to the expediency of working it by stationary engines, and estimates of the expense were made by competent engineers. The total amount of capital to be invested in mov

ing power was estimated at about 120,000l.; of this above 25,000l. was devoted to ropes, sheaves, drums, and other necessary accompaniments. The total annual expense of maintaining the moving power was estimated at 42,000l., and of this about 18,000l. was appropriated to the wear and tear of ropes, sheaves, &c. &c. Thus it appears that the method of transmitting the power of the stationary engines to the trains by ropes would absorb about 20 per cent. of the invested capital, and their maintenance would consume about 43 per cent. of the annual expenditure.

Another source of comparative economy would obviously be the diminished number of stationary engines. In the estimate already referred to, it was calculated that the distance of 30 miles should be divided into 17 stations, with two 40-horse engines at each station; besides these, there would have been two engines at the bottom of each inclined plane, one at the tunnel, two at the top of the planes, and one at the Manchester end, making in all 42 stationary engines to work a line of 30 miles. Now, according to the estimate of the patentee of the Pneumatic Railway, from three to six stations would be sufficient between Manchester and Liverpool, and the whole line would be worked by from six to twelve steam-engines. Putting aside, therefore, the saving of power which would arise from the substitution of suction in the tunnel for ropes, and supposing the amount of stationary power in both cases to be the same, it will be evident that a material saving would arise from the circumstance of that amount of power being derived from so much less a number of engines-the number of enginemen, assistants, &c., besides the interest on capital, being considerably less.

Some notion of the economy of power likely to arise from superseding the use of ropes may be collected from the result of experiments made by Messrs. Stephenson and Locke, on the resistance arising from the friction of ropes. They found that a load of 52 tons, drawn by stationary engines worked by ropes, through mile and half stages, offered a total resistance amounting to 11,56 lbs. ; of this 582 lbs. arose from the friction of the load, and 574 lbs. from the friction of the ropes. In the case of the Pneumatic Railway, the friction of the rope is replaced by the friction of the air-pumps and of the impelling apparatus; and it will be evident that the latter, compared with the former, must be almost insignificant. Hence the power wasted in its transmission from the stationary engines to the load, which in one case amounts to 50 per cent. of the whole moving power of the engine, in the other is of comparatively trifling amount.

Slopes on railways will always be objectionable, whatever power be used; for even

the most gentle ascent will increase the resistance of the load in an enormous proportion. The difficulties, however, which they present are materially less when the line is worked by stationary than by locomotive-engines, and would be still further diminished by superseding the rope; the resistance arising from the rope being always greater on inclined-planes than on the level, owing to its increased thickness and consequent weight. A load which requires a 4-inch rope for the level requires a 5-inch rope upon a slope of 1 in 100. The weights of equal lengths of these ropes would be in the proportion of about 2 to 3, the slope requiring one-half more weight of rope than the level. Besides this, the moving power on a slope, in addition to the ordinary friction which it has to overcome on the level, has likewise to draw up the weight of the rope-a resistance which will be increased in proportion to the acclivity of the slope.

The disadvantages produced by slopes when locomotive-engines are used are still more formidable. The same engine which is fitted to work upon the level is altogether inadequate for the slopes; the consequence of which is, either that the locomotive is strained beyond its power by working up the slopes and rapidly destroyed, or that the engines must be more powerful than is requisite for the common level of the road, and thus power and expense wasted; or finally, that an auxiliary engine must be kept constantly ready at the foot of each slope, with its fire lighted and its steam up, ready to help up the trains as they arrive. Unless the trains be almost incessant (which even on the most frequented railroad they never can be), this last expedient, which is the one adopted on the Manchester line, is attended with great waste of power and expense. Stationary engines worked on the pneumatic principle would effectually remove all these difficulties and objections.

The weight of the trains which could be drawn upon the Pneumatic Railway, and the speed of the motion imparted to them would entirely depend upon the power of the stationary engines. As the friction or other resistance does not increase with the velocity, the same absolute expenditure of power would draw the same load at whatever speed. The high speed attained by locomotive engines has been attended with great expense, but this has not arisen from the increased expenditure of power. It has been caused by the wear of the engines themselves, consequent on their rapid motion on the road, and by the necessity of sustaining a fierce temperature in the fire-place, in order to be able, within the small compass of these engines, to generate steam with sufficient rapidity to attain the necessary rate of motion. As the