Sir,-Seeing in the Mechanics' Magazine for December 1841, a letter from our talented townsman, Mr. Robert Mallet, explaining the particulars of what he calls his Hydro-pneumatic Buffer, I beg leave to offer a few remarks on the subject. Having peculiar opportunities of witnessing several experiments, and having paid particular attention to his buffer while in use, I can state that the piston, or buffer bar, when forced towards one end—which could only be by violent concussion-never reacted so as to adjust itself in the position before struck at the centre. This was one great fault, and I believe the principal cause why it was so soon abandoned. Another defect was the awkward position of the buffing cylinders as regards the rail on which it was placed, as the two air vessels stood above the bottom boards, and inconveniently monopolized a portion of the space intended for the accommodation of passengers' feet. Altogether it was much too large and heavy, and offered an unnecessarily rigid and very unpleasant resistance to all ordinary shocks, such as the stopping or starting of the train. When placed alone on the railway, and struck with any heavier moving body, the buffer scarcely acted except as a rigid bar, because the power requisite to overcome the traction of a light coach (such as the one in which it was placed, which might be moved by a force of from ten to fourteen pounds,) was incalculably less than that required to compress such a body of air, with the additional resistance from friction of the buffer bar at each end, the two stuffing boxes, and heavy centre piston unsupported for 6 or 8 feet. The only time the buffer might be said to act from the effect of an ordinary shock, was when the cylinder was minus a portion of the water, which was constantly oozing out at the stuffing-boxes, at which time, if struck, it would sluggishly move forward till relieved, and then react through a portion of the space before traversed, but so slowly as to be scarcely perceptible -a defect which must have been owing to one of two causes, the resistance to the friction above mentioned, or the escape of water over or around the centre piston.

I have no doubt this buffer may be so modified as to resist the shock of a train, if fixed at the terminus of a railway; or

for a heavy locomotive engine, if the attendants were very assiduous, and sufficiently philosophic, so to ascertain the exact amount of unknown quantities, as to know when the injected air would be of equal density at either end. The adoption of such a system of buffers would, however, be the means of providing employment for many persons more than are ordinarily required.

There is one paragraph at the conclusion of Mr. Mallet's letter, (page 420,) to which I shall briefly allude. Mr. M. says, "This buffer continued in use a long time upon the Dublin and Kingston railway-as long, I believe, as the under carriage lasted-and at length fell into disuse from neglect, as standing isolated in the midst of a different buffing system." The "long time in use" was, on an average, part of one day in each week, for a few months, and then only in cases of the greatest necessity, on account of the extra weight of the coach, and rigidity of the buffer; the "carriage" in which it was fixed is still in daily use, since the Hydropneumatic buffer was removed at the desire of the person who employed Mr. M. to have it made; and as to its being "in the midst of a different buffing system," it was so only in form, not in system, as it is stated in a former page to be on "the same system of thorough buffing as that invented by Mr. Bergin."

But to pass on to what Mr. Mallet considers an improvement in the application of these buffers for railway use in general, namely, the scheme of placing a buffer "in the thickness of the roof of a railway coach." Certainly this is a perfectly novel and original idea; but I fear the application of it would be practically defective, as it would be found difficult so to frame a coach-body, as to have the roof sufficiently strong to resist any considerable shock. Making use of the roof as a place of resistance would indeed be using a destructive lever of the first order to crush the coach-body, as the pillarstechnically so called-have little or no other support but at the bottom, into which they are, and must in all cases be framed. I also fear Mr. M. has fallen into error respecting the point in which the centre of gravity of a railway coach is situate, as the wheels, axles, and bearing springs are, in all cases, at least of equal weight with the body, and the buffers are gene

rally placed on the upper side of the carriage, which is in all cases very heavy; consequently, the line in which the centre of gravity falls must be somewhere under the centre of the buffers, in every carriage so constructed; for which reason I can state, from much experience, that in nine cases out of ten, whatever be the nature of the collision to a railway train, the coaches are never totally upset. I have known instances of the breaking of axles, but in no case did the carriage ever tumble over; and of one wheel breaking into fragments, and yet the coach remained on the other three. In conclusion I would say, that if the roof buffer be intended to be at all practically useful, it ought to be equal in size and strength to those in the under carriage, as working in conjunction with them; but as it is recommended to be smaller, and consequently weaker, and as "partial weakness is the weakness of the whole," it must, I presume, on that ground alone be objectionable.

In the year 1835, I proposed to have a piston to compress air at atmospheric pressure in a cylinder, as a simple substitute for railway coach buffers. I considered, that as the compression would be at all times momentary, there would be no escape of air of any consequence to prevent effective working, with ordinarily well-packed stuffing boxes. The person to whom I proposed this plan, immediately employed Mr. Mallet, of Dublin, to have one made, allowing him to improve on my suggestion; the result of which was-in order to overcome an imaginary defect the use of water, to prevent the escape of air, as if the pressure was intended to be uniformly continuous, and not momentary, as in every case. But what I considered a decided improvement on the experimental one, and which would prevent the necessity of pumping in air or water at any time, would be the plan, of which the following sketch is a longitudinal section. This buffing cylinder is intended to be of wrought iron, or coarse brass, 6 feet in length, and about 4 inches in diameter, with two separate pistons, and an ordinary stuffing-box at each end, through which the piston rods, or buffer bars, continue beyond the ends of the carriage, to receive the buffer heads; on the top of the cylinder at the centre, is placed two small hinged valves-one within the other

139

the inner to open inwards at all times when at rest; the other, or rather both, to open a small portion outwards against a small stiff spring, proportioned to resist all ordinary concussions; this latter to act as a safety-valve to prevent the explosion of the cylinder, should the pistons

be forced together by any extraordinary shock, or collision: from this it must appear evident, that as at all times the approximation of the pistons towards each other would be momentary, there would be a partial, or nearly perfect vacuum between them and the stuffing boxes, which, acting in conjunction with the rarified air in the centre, and ultimately, the ingress of atmospheric pressure at the valve, would altogether, when re

THE LITTLE WESTERN.

Sir,-In your last Number, (966,) there is a paragraph copied from the Times, respecting the performance of the Little Western steam-boat. It is there stated that "she was accompanied down the river by one of the fastest boats, viz., the Railway, for which she waited off Galleons, and with which she contested, head and head, to Gravesend." Now, I do not wish in any way to depreciate the powers of the Little Western, being, as they profess her to be, the best boat that has been turned out from the western districts; but at the same time I must say, that had the advocates for Bristol boats and machinery been more candid in their representation of facts, it would have been much more to their credit. That the two boats went head and head into Gravesend, I do not for one moment dispute; but they must remember, that, after the fair start off Galleons, the Railway kept gaining, and it was not until

a stoppage at Purfleet, where the Railway had to land five passengers, (four ladies and one gentleman,) that the Little Western came up to her, and, from the well known attraction of two boats in close juxta-position, the Railway could not get away from her opponent before their arrival at Gravesend; so much for the head and head match, as it is represented.

It is much to be regretted that, in the reports of the performances of steam-boats, no mention is made of the fuel expended. Now, I have ascertained from the most authentic sources, that the fuel consumed in the Railway is about six hundred weight and three quarters per hour, being at the rate of about eight pounds per horse power per hour; while the rumoured consumption of the Little Western is thirty-three hundred weight, being at the rate of about twentythree pounds per horse power per hour. Now, if this be true, (and if not, they can contradict it, and say what it really is,) or taking the expenditure of fuel at only double that of the Railway, surely convenience and rapidity must be very imperative indeed, to induce speculators to supply the public with them at such a rate. If this is all the London engineers have to compete with, their task is indeed easy.

I am, Sir, yours, &c.,

X. Y. Z., (passenger per Railway.) London, Feb. 15, 1842.

If

Sir, I have attentively perused Messrs. Palmer and Perkins's description, in No. 963, of what they are pleased to style an improvement on that "most important," but much abused article, the common pump. their pump be so efficient as they allege, will you permit me to ask why they have drawn it with so short a suction-pipe? It is quite ridiculous to talk of testing the capabilities of such a machine for mining purposes with a five, or even fifteen feet lift. Again, as to their wonder-working valves - were they

Derby, February 8, 1842. simply discs "cut diagonally out of a solid cylinder of the same diameter as the bore of the pump-barrel," there could be no doubt that, at the proper angle, they would "fit the barrel with the greatest accuracy;" but doing so, it would be impossible they should work on their spindles and to enable them to take the position of the open clack, as shown in fig. 3 of Messrs. Palmer and Perkins's drawings, the disc must be reduced nearly ths of an inch on each side, as set out in the subjoined diagram for a ten

inch pump. A wonderfully efficacious method, this, of rendering them fit for retaining liquids, gases, and steam! With respect to the trial at Mr. Robinson's, it proves, in my

judgment, nothing beyond the facility with which plausibly described experiments may be made to fit and (apparently) to corroborate almost any sort of foregone conclusion. He

PILBROW'S CONDENSING CYLINDER ENgine.

Sir, I must again intrude upon your kindness, and solicit space enough in an early number of your Magazine to thank your valuable correspondent, "Scalpel," for the bold manner in which he has spoken of my engine. I doubted not, judging from the past, and the interesting papers which have emanated from him, but that such would be the case, whether for or against.

66

Scalpel" is the first, I think, of your correspondents who has had temerity or good opinion enough to pronounce decidedly in favour of my invention, but I fear not that many, ere long, will join him.

It is but justice, perhaps, to myself, that I should at the same time inform "Scalpel," that his friendly suggestion of " "increasing the area of the condensing cylinder" was done by me many months ago, and that the drawings in the hands of the manufacturers are made so; not that I apprehended any jar, or found that the piston, when discharging the condensement, travelled any faster than the ordinary air-pump bucket, the steam piston travelling at the usual speed; but, upon the whole, there were advantages to be gained from such an arrangement, and it lessened, sometimes, the prejudice of those I met upon the subject.

I am, Sir,

Your obliged servant,
JAMES PILBROW.

Tottenham-green, Feb. 12, 1842.

LAW OF PATENTS-DEFECTIVE SPECIFICATIONS.

Court of Queen's Bench, Westminster, Feb. 12.-(Sittings at Nisi Prius, before Lord Denman and a Special Jury.)

The Queen v. Nickels.

This was a scire facias to repeal a patent which had been taken out in respect to the braiding-machine to which the defendant had made some additions and improvements.

The Solicitor-General, Mr. Erle, and Mr. Hindmarch, appeared for the Crown; the Attorney-General, Mr. M. D. Hill, and Mr. Hoggins, for the defendants.

141

The Solicitor-General, before entering upon the merits of the invention, submitted to the Court that it would be a mere waste of time to call any witnesses, or enter into any inquiry about the circumstances of the case, as the specification upon which the patent had been founded was illegal and void. The patent was for additions to and improvements in a machine already in existence; and it was a fundamental principle of the patent law, that in such cases the specification should clearly and precisely define the part of the machinery to which the patent was applied. Without such a statement, it would be ob viously impossible for the public to know what part of the machinery they were prevented from using during the period for which the patent was to run. The learned gentleman further contended, that the specification did not so describe the nature and construction of the invention itself, as that any person in the same trade could make and apply it as soon as the period for which the invention was protected by the patent should have come to a termination. As the specification was therefore illegal with respect to the two capital objects for which every such document was required by law, it became altogether unnecessary to enter into the other parts of the case.

The Attorney-General, on the part of the defendant, submitted that any intelligent workman connected with this particular business could see, with the help of the drawing annexed to the specification, what part of the machinery was new, and what was old; and the learned gentleman proposed to give evidence to that effect.

Lord Denman, however, was clearly of opinion that the material parts of the specification were inadequate when taken severally, and inconsistent when taken together. Such being the character of the specification, his lordship was of opinion that it would be a mere waste of the public time to hear any evidence upon the subject; and his lordship directed the jury, therefore, to return a verdict for the Crown.

The Attorney-General then tendered a bill of exceptions, which was received.

Court of Queen's Bench, Westminster, Feb. 14.-(Sittings at Nisi Prius, before Mr. Justice Wightman and a Special Jury.)

Cooke v. Pearce and others.

This was an action for the infringement of a patent which the plaintiff had taken out for an improved method of working what are called "German windows," in barouches and other carriages of that nature to which windows of that sort are applicable.

The Attorney-General, (with Mr. Hoggins,) appeared for the plaintiff, and called

witnesses, who proved that the method and machinery in question were highly useful and advantageous to the public, within the range in which it could be applied, and that the plaintiff was the first person that had so applied it.

Mr. Erle, (with Mr. H. Hill,) appeared for the defendants, and submitted, first, that the improvement in question was not the proper subject of a patent at all, as it consisted merely, or principally, in the application to the window of springs, the nature and quality of which were perfectly well known to the public for a very long period of time; second, that the specification did not describe with sufficient accuracy the nature of the invention, for that the old and new parts were not properly distinguished from each other; and, third, that in stating that the invention was applicable to carriages, the patentee claimed too much, for that it was not applicable to chariots and close carriages, and the patent having claimed more than could be supported, the patent became void on that account.

A great deal of discussion arose upon these objections, and it was ultimately agreed between all parties to put certain facts upon the record in the shape of a special verdict, upon which the judgment of the Court above is to be taken upon a future occasion.

ABSTRACTS OF SPECIFICATIONS OF ENGLISH PATENTS RECENTLY ENROLLED.

WILLIAM EDWARD NEWTON, CHANCERYLANE, CIVIL ENGINEER, for improvements in the manufacture of fuel. (A communication.) Petty Bag Office, January 7, 1842.

This fuel, to which the name of "Carboleine" is given, is thus produced. A quantity of coal, charcoal, coke, brown coals, or peat coals, being reduced to a fine powder, is put into wooden tubs and mixed with oil; two and a half parts of water, to one of clay or loam, are then added, and the mass worked into cakes by hand or machinery. These cakes being afterwards gradually dried, by the application of fire-heat, become nearly as hard as stone, and in burning are said to give out more heat than any other known combustible.

Should a fuel capable of producing a still more intense heat be required, oil and fluid tar are combined with powdered coke and coals. The proportions of the ingredients for three qualities of carboleine are given as follows:

No. 1. Twenty-four parts coal, six or seven of clay water, one of oil, and one of bitumen.

No. 2. Twenty-four parts coal, six or seven of clay-water, and two of oil.

No. 3. Forty parts of coal, thirty-six of clay-water, and four of oil.

JOSEPH RATCLIFFE, OF BIRMINGHAM, MANUFACTURER, for certain improvements in the construction and manufacture of hinges for hanging and closing doors. Enrolment Office, February 3, 1842.

A lever, to be screwed or otherwise attached to the under side of the door, is mounted on the square head of a vertical axis, the upper end of which is supported in the brass cover, while its lower end works in a cylindrical cavity of the cast-iron box within which the mechanism is placed. Near the lower end of the axis a segmental plane is affixed, with its upper surface inclined to an angle of about 70°. Within the box, and turning on a horizontal axis, is placed a broad lever, at the end of which there are two small rollers, disposed at such a distance asunder as to rest upon the two edges of the segmental plane; from this lever, immediately over the horizontal axis, rise two arms or levers, at right angles with the former, carrying between them a swivel nut, stepped to form abutments for two strong helical springs placed one within the other. This part of the mechanism is screwed down into the cast-iron box which forms the base of the hinge, in such a position, that the two small rollers rest one on each side of the inclined segmental plane. At the back part of the box there is a metal plate, carrying a screwed pin, upon which a stepped nut is mounted, opposite to the swivel just before described. Between these nuts two strong spiral springs are placed, the pressure of which can be adjusted by screwing backward or forward the hindmost nut, four holes being made in its circumference to admit a lever for that purpose. On opening the door to which this apparatus is applied, the inclined segmental plane is brought under one of the rollers and raises the broad lever, which pushes back the swivel nut and compresses the spiral springs; the reaction of these springs upon the inclined plane turus the axis, and closes the door.

The claim is, 1. To the general arrangement of the parts of a door-hinge, as described and illustrated; 2. The use of the swivel nut for receiving and transmitting the pressure of the springs to the levers.

JOHN LEE, OF NEWCASTLE-UPON-TYNE, MANUFACTURING CHEMIST, for improvements in the manufacture of chlorine. rolment Office, February 4, 1842.

En

These improvements consist in manufacturing chlorine by the use of retorts or ovens, which are so arranged as to have the heat required for the process transmitted downwards, through the covering or arch of the oven or retort. In the drawing accompanying the