166, Fleet-street, London; and 99B, New-street, (Of which firm Mr. J. C. ROBERTSON, the EDITOR of the MECHANICS' MAGAZINE from its commencement in 1823, is principal partner,) For England, Scotland, Ireland, and all Foreign Countries, and the transaction generally of all busi- Specifications Drawn or Revised. DISCLAIMERS, AND MEMORANDUMS OF ALTERATION PREPARED AND ENRolled. Caveats Entered and Oppositions CONFIRMATIONS AND PROLONGATIONS INTENDING PATENTEES supplied gratis with Printed Instructions, on Application, either per AGENTS: For Manchester, Messrs. Wise and IT has long been the opinion or many Scientific Men, Inventors and Manufacturers, that it would be of the greatest utility to establish in some central part of Europe, a Consulting Agency Office; directed by an experienced Engineer, who might assist Inventors by his experience and advice, to procure Patents (Brevets) and prepare the requisite papers, and to promote generally the interests of Influenced by this prevailing feeling on the sub- ject, M. JOB DIXON, consulting Engineer, Knight of the Netherlands Lion, &c., has, at the solicita- tion of numerous scientific friends in England and the Continent, opened a Patent Agency Office at Rue d'Artifice, 84, bis, Boulevard de Waterloo. Where orders will be received for the Procuration of Patents of Invention for the various States of Europe, and the United States of America; and where Mr. DIXON may be personally advised with on all matters relating to the Securing of Patents for Inventions or to the working of the same. Persons favouring M. DIXON with their com- mands, may rely on the most judicious care, con- THE BIRMINGHAM PATENT IRON TUBE COMPANY Manufacture Patent Lap Welded Tubes, under Mr. Richard Prosser's Patent, for Marine, Locomotive and all Tubular Boilers. Also Tubes for Gas, Steam, and other purposes. sorts of Iron Gas Fittings. Works, Smethwick, URWIN'S PATENT STEAM ENGINE IMPROVEMENTS. [Patent dated January 11, 1849. Patentee, Robert Urwin, of Ashford, Kent, Engineer. Specification enrolled July 11, 1849.] MR. URWIN'S improvements are calculated, by the extraordinary advantages which they offer, to command general attention; and if these advantages are realized to but half the extent anticipated by the inventor, they will mark an era in the history of the steam engine. They embrace two main objects:-first, how to get the greatest possible effect from a given quantity of steam within a given time; second, how to get back that steam-recondensed, reheated, and reevaporated-without waste, or at least with all such waste as may occur amply compensated for. And supposing these problems to be solved successfully, or even with only very partial success, we should be enabled to do by steam power, much that we have never been able to accomplish by means of it before-in ocean navigation and screw propulsion especially-and to obtain in all cases from it far better service, at much less expense. First Branch. Mr. Urwin observes that, "in the ordinary condensing or low-pressure steam engine, the motion of the piston is produced either by steam of low pressure (say from five to ten lbs. per square inch), or by means of the pressure of the atmosphere alone, acting on one side of the piston against a vacuum of more or less completeness, produced on the other by the condensation of steam; and that several attempts have been made to increase the efficiency of such engines by increasing the pressure of the steam (say to 15 lbs. and upwards), but without the proportional advantage anticipatedThat in the ordinary non-condensing or high-pressure engine, the motion of the piston is produced solely by the pressure of steam; that is to say, by an inflow of steam of high pressure on one side of the piston acting against an outflow of used steam of less and constantly diminishing pressure on the other side, in which case, the force exerted on the inflow side is, of necessity, proportional to the velocity and completeness with which the clearance of the steam from the other or exhaust side is effected-And that both sorts of engine fall short of developing the full motive force due to the quantities of steam consumed by them respectively, owing to the slowness or imperfection of the methods employed to get rid of the air or steam on the exhaust sides of the piston." Having cleared the way by these observations to the truth of which no exception can be taken-Mr. Urwin proceeds thus to describe the scope of his first improvement: Now, the first of my improvements in steam engines consists of a method or system of effecting the clearance or exhaustion, whereby I am enabled to combine in one engine the advantages peculiar to both the condensing and noncondensing, or low pressure and high pressure engines, and to obtain from given quantities of steam within given times, a greater amount of work or duty than I believe has been ever before obtained from like quantities in the like times; and this without the aid of the ordinary air-pump." The details of the method or system then follow: "Figs. 1 to 10, both inclusive, show the manner in which this improved mode of clearance or exhaustion is applied to an engine suitable for locomotive purposes. Fig. 1 is a vertical section of the cylinder and piston, and their immediate appendages, taken on the lines a, b, a of fig. 2, which is a cross section on the line d, e. Figs. 3, 4, 5, 6, 7, and 8 are plans of the piston on the lines respectively marked fg, h i, k l m n, o p, and qr. Fig. 9 is a sectional elevation of a locomotive carriage, with a pair of such engines fitted to it; and fig. 10, a plan on the line st of fig. 9. "A, is the cylinder, which is longer in proportion to the stroke than usual, and instead of being entire in the sides from top to bottom, as usual, is made with an opening, B, at the middle, all round, with the exception of four connecting pieces or ribs, vv (see fig. 2;) C, is the piston, the constructive details of which are clearly shown in the sectional plans of it given in figs. 3, 4, 5, 6, 7, and 8. It is made of such a depth in proportion to the length of the cylinder, that when the piston has reached the end of its cylinder, and terminates in a valve-box, E, at one side, which is kept closed against the atmosphere by a spring-stalk valve, Ea, but yields readily to any pressure exceeding the weight of the valve. From this jacket or casing the steam, which rushes into it through the opening, B, may be either allowed to pass into the open air or conducted into the chimney of the locomotive, to act as a blast. FF, are two ports, one at the top and the other at the bottom of the cylinder, which serve alternately as inflow and outflow passages for the steam to and from the cylinder, in the same way as in ordinary engines. G, is the exhaust-passage, which leads to a small condenser, H, (not shown in fig. 1;) K, is a slide-valve box, which differs in no respect in its details from ordinary slidevalve boxes. "The operation of the engine is as follows:-Let us suppose the parts to be in the position represented in fig. 1, that is to say, the piston at the bottom of the cylinder, the communication just about to open between the upper part of the cylinder, A, and the exhaust-passage, G,, |