PARKIN'S PATENT CONCRETE RAIL- [Communicated by the Inventor.] It is now admitted by all scientific men of eminence that for rails longitudinal, continuous, wooden bearers are much preferable to either stone or wooden isolated sleepers; and that concrete forms the best foundation, while, in respect to economy, the above combination admits of no comparison with other modes of construction. Nearly three years ago Mr. Parkin laid down some rails at Llanelly on continuous wooden bearers and a concrete foundation, and the railway, though in constant use, continues as perfect as when made, having, with the exception of a few screws being replaced, required no repairs whatever, while none will be required for years to come; the statement of which fact, as railway proprietors in general now find their returns not to be commensurate with their outlay, will, doubtless have its effect. The Safety Railway Wheel. The wheels and axles of railway carriages often break from the severity of the concussions produced by high speed; and it is of vast importance to lessen this danger. Mr. Parkin's wheels will effect this object, as the wood will run on the rails, and the effect be the same as on wood pavement, the immense value whereof the public have the means of appreciating. In the ratio that noise and jolting cease, security and ease in travelling increase, and wear and tear decrease; while the first cost of the wheels, and that of keeping them in repair, are much lessened. Each wheel is made with 24 sectors of wood a,with the grain extending from the axle in the direction of the radius, and are held firmly together at the centre by two cast iron wheels b, and 12 bolts and nuts d; and at the periphery, by a cast iron flanch c, drilled, about 5 inches deep, (which enters a rebate turned in the sectors, and is further supported by 12 arms, or spokes, fitted in between the The plans described in this article (with the exception of the connection of the three wheels,) form part of the same patent as includes the dimensions described in our 852 nd and 858 th numbers; the patent is dated April 9th, and the specification enrolled Oct. 9 th, 1839. outer circumference of the cheek and the inner circumference of the flanch), a corresponding wrought iron ring, and an equal number of bolts and nuts. The sectors are well boiled, and the joints crossed, to insure rotundity. The sectors and flanch will wear a long while, but can be replaced when requisite, every other part of the wheel being of indefinite durability. Besides a transverse view of the wheel, the drawing represents three wheels for a locomotive engine, a band passing from the nave of the driving wheel to the nave of each of the other wheels, in order to relieve the driving wheel of part of the stress thrown on it in giving motion to the train, according to the plan about to be adopted on the Sheffield and Rotherham Railway. As the driving wheel may be made of any convenient width, the necessity of the flanch is dispensed with, and such wheel can consequently be made for less than half its present cost. Before this will appear in print, some of the wheels will doubtless be in use on the Eastern Counties Railway. THOS. PARKIN. 25, Moorgate-street, City. Description of Engravings.- Fig. 1, a side view of three railway carriage wheels connected as above described. Fig. 2, an edge view of one of the wheels. Both these figures show the wheels upon the improved concrete railway-which is partly shown in section. a a, the wooden sectors; bb, the iron rings joining the sectors; dd, bolts and nuts securing the rings and sectors; cc, cast iron Hange; e e, rope or band connecting the three wheels; ff, the pullies on the naves of the fore and hind wheels; y, the pulley on the nave of the driving wheel. hhh, the longitudinal wooden sleepers; ii, the sails fastened thereto by pins or screws; k k, the concrete foundation. INVENTION OF MERCURIAL LETTER AND MONEY BALANCES-BURSILL'S IMPROVED BALANCE. Sir, Some years ago I had a mercurial balance constructed for testing the weight of gold coin, and by greatly reducing the diameter of the piston, the SIR J. E. ALExander on developing THE POWERS OF THE VOICE. 419 instrument was rendered so delicately sénsitive that I was enabled to substitute it with advantage for a pair of assay scales, it being made to indicate most distinctly even the fractional part of a grain.* I must candidly acknowledge that it is only recently I applied the same principle of construction to a letter balance, one of the latter I had made for me by Messrs. Tagliabue and Casella, of 23, Hatton Garden, whom I had put in possession of my designs; after which a notice was pointed out to me in your scientific work, showing that the priority of the invention was already in dispute between a Mr. Miller, of Dundee, and a Mr. Osler, of Birmingham. The principal difference between the mercurial balance described in your Magazine, and my registered letter balances, as manufactured by Messrs. Tagliabue and Casella is, that I employ a moveable instead of a fixed scale; so that the operation is enabled to start fair, notwithstanding any rise or fall of the piston that may have been induced by a change of temperature acting upon the mercury. The instrument also is portable, without any danger of spilling the mercury; and is adapted to the weighing of gold coin, &c. In others, I make use not of a cylindrical, but of a half round piston (as being more sensitive,) the flat side of which preventsit from turning round, while the result is registered by a little moveable indicator placed above the mercury. My brother, however, has adapted the instrument to weighing machines in general in a manner which will, I think, receive your unqualified approbation, which he will be happy to communicate as soon as it is secured to him. Owing to the publicity that has al *The subjoined is a letter in verification of this statement from the person who made the balance referred to. Sir,-About six years ago I made a mercurial balance for Mr. G. Bursill, to be used for trying the weight of sovereigns, &c.; my recollection of the circumstance is very distinct, as the tube I employed in the first instance was a piece cut off an old gun barrel, plugged up at the bottom with soft iron bought at Redmund's foundry. I have always heard say that the action was perfect. I remain, Sir, your obedient servant, PETER SCOTT. 15, Wellington-street, Pentonville, Feb. 27, 1840. ready been given to the principle upon which instruments of this kind generally are constructed, I shall feel greatly obliged by your notice of these facts, having no doubt that I shall be enabled to afford the most ample proof when called upon of my being the first inventor of the mercurial balance. Mr. G. McLeod, of Stoke Newington has suggested to me, that in order to save trouble to the numerous postmasters, when the new stamps shall come into operation, it would be desirable to have a machine placed behind the opening of their respective letter boxes, and so constructed as to at once weigh and deliver the letters into separate chambers agreeably to the prices charged for posting; should any of your ingenious correspondents devise a practical and expeditious method of effecting this object, I should say they would find their advantage in bringing it into operation. In conclusion, may I be allowed to thank you for your unsolicited attention in one of your former numbers to an invention for which my brother and self received a reward from the Society of Arts; I allude to your notice of "A. Bursill's condensed air lamp and breathing apparatus for miners." I am, Sir, Your obedient servant, SIR J. E. ALEXANDER ON A MECHA- Mr. Editor,-As it is the duty of every one to communicate whatever may be of advantage to the community, as an old subscriber to your valuable periodical, I beg to state that lately great benefit has been derived by some children with defective utterance, by being made to read slowly and distinctly for half an hour, or more, each day, and keeping at the same time between the front teeth a thin slip of wood, so as to open the mouth from three-fourths of an inch to one inch. Demosthenes, the orator, we read, cured his defective utterance by stones in the mouth, doubtless for no other purpose than to keep it open in speaking-this semi-gagging system then with DOUBLE BLAST BLOW-PIPE. some advantage over others that I have seen, I take the liberty of forwarding a sketch of it, for insertion in your Magazine, if you think well. I agree with the ingenious Mr. Riddle, that the old and well known principle of the bent lever balance is well adapted for a letter-balance, if made in the oldfashioned way, with the scale at the extremity or greatest radius of the levers, by which means the divisions are of course larger than in any other arrangement. In my balance, which weighs up to four ounces, the ounce is divided into 16ths or drams, which measure in the first half-ounce near one-eighth of an inch each, and much more in the second and third ounces. Instead of a hook, which is only adapted for small letters when folded, use a flat scale-board, made of thin ivory, with a simple parallel motion to keep it level. This renders the apparatus available for weighing small articles, which could not be at all suspended on a wire hook; besides plans, open papers, or rolls of plans, &c., previous to folding. There is another little addition necessary to the accuracy of any weighingmachine upon the bent lever principle, 421 namely, some means of bringing the index to zero before using, without any thing in the scale, which will not be the case if the instrument stand at all out of level. My balance stands upon three points alone, one of which is the rounded end of an adjusting screw, by turning which, if necessary, the index is brought to zero of the scale, with the greatest nicety. The foot and frame of my machine is made of mahogany, radius of quadrant 7 inches, total height 10 inches, the gradiator quadrant of ivory, the divisions being obtained by absolute weight put in the scale-board, the lever, spindle, and parallel motion of iron. For post-offices and places of large business, I can scarcely imagine any apparatus which would afford greater facilities in use; expedition, from the facility of placing any formed article on the scale, followed by the immediate result shown by the index, and accuracy from the magnitude of the divisions. I am, Sir, your obedient servant, GEORGE EDWARDS. Lowestoft Harbour, Jan. 30, 1840. DOUBLE BLAST BLOW-PIPE. Sir,-Should you be of opinion that the annexed sketch of a blow-pipe is at all feasible, or likely to increase the heat of the flame produced by the current or blast from A, (as in the ordinary simple blow-pipe) by another jet of air crossing it at B, (both jets being produced simultaneously by the blower), you will oblige me by inserting it in your excellent Magazine. The experiment has not yet been tried, but it seems worthy of a trial. If the heat is increased (as we know it to be) by the first projected flame, why should not that also be rendered more intense by additional excitement from another current of air, and consequently a greater supply of oxygen? Your obedient servant, Feb. 22, 1840. J. B. |