working, further explanation is unnecessary. If you would favour me with a remark, in your next number, concerning its practicability, you will oblige Your most obedient Servant, A. T. MATHER. We see no other practical objection to the working of an engine on this construction, but that which is found in all rotary engines, (viz.) the difficulty of keeping the joints tightly packed.-EDITOR. Scientific Notices. REPORT OF TRANSACTIONS OF THE INSTITUTION OF CIVIL ENGINEERS. (Continued from page 378, Vol. XVI.) "On the autogenous uniting of Lead and other Metals." The term 'autogenous' is employed by the inventor, M. de Richemont, of the method now described, to designate the union of pieces of metal of the same kind with one another without the intervention of the ordinary alloys of tin or other connecting medium. This is effected by directing, by means of a fine beak, the flame of a jet of hydrogen on the parts to be united. A complete fusion of the metal is thus effected, and the parts are united in one homogeneous mass, the metal at the points of junction being in the same state chemically as at the parts untouched. Plates of any thickness, whatever the direction of the edges to be joined, may thus be perfectly united, and the lines of junction made as strong as the rest of the mass. Many circumstances contribute to render the joints made with common solder objectionable. The rates of expansion and contraction on changes of temperature for lead and its alloys with tin are different; some chemical agents act much more on alloys of lead and tin than on lead alone. The alloys also are fragile, and the solder may not perfectly attach itself, without the imperfection being observed. In addition to obviating these objections, M. de . Richemont conceives that his new method of union possesses the farther advantages of economy, in saving of solder, and in avoiding seams and overlappings; in permitting the use of thinner lead, and the use of lead where it is now inadmissible, and in rendering practicable the repairs of vessels which are now impracticable. M. de Richemont also applies this jet of flame to heating the common soldering irons used by tinmen and plumbers. The jet is permitted to play upon the tool, which, in a few seconds, is brought to the requisite heat, and maintained at that heat without any injury to the tool. The heat can be regulated to the greatest nicety by diminishing or increasing the jet. The author conceives that the sulphate of zinc, produced in the manufacture of the gas, will be found of such value as greatly to diminish the cost of this process. March 3, 1840. The PRESIDENT in the Chair. "Description of the Nonsuch' Iron Passage Boat, plying on the Limerick navigation, between that place and Killaloe." By Charles Wye Williams, Assoc. Inst. C. E. The attention of Mr. Williams having been attracted to the successful plan for the conveyance of passengers adopted on the Glasgow and Paisley Canal, where light sheet-iron boats, of great length, travel at a speed of nine miles an hour, he was induced to attempt the introduction of the same system on the Irish canals. A great difficulty, however, presented itself, as the locks there would only admit boats 60 feet long, which length was quite inadequate to the carrying out, with advantage, the principle involved in the long light Scotch boat. To overcome this difficulty, he constructed a sheet-iron boat, 80 feet long and 6 feet 6 inches wide at midships, having the stem and stern ends (each 10 feet long) attached by strong hinges to the body, and susceptible of being rapidly raised to a vertical position by means of winches; thus reducing the length to 60 feet when required to pass through a lock. It is evident that by this means there would be gained not merely the apparent additional buoyancy of 10 feet at each end of the boat, which from the form would not be very effective, but in reality the buoyancy due to an addition of 20 feet of the midship section. The boat thus constructed has been found to answer perfectly; the buoyancy is equal to that of the Scotch boats of similar dimensions; no crankness or unsteadiness accrues when the ends are raised; it is capable of carrying 60 passengers, travelling at a speed of 9 miles per hour, with the same power that was required to draw a 60 feet boat with a less load; and there is a much less action on the canal bank in consequence of the increased length, which at the same time imparts stiffness, and enables passengers to enter and leave the boat with safety. Considerable time is saved in passing the locks, by the opposition of the square end when the bow is raised; the boat may thus be run almost at full speed into the lock, and both ends being raised simultaneously, it is stopped much more easily than if the tapered ends were down. No provision is necessary for keeping the ends down, as the weight of the bow and steersman answers the purpose. This boat has been working, without intermission, for three years, between Limerick and Killaloe, traversing twice daily a distance of 15 miles, on a navigation of considerable intricacy, and passing 11 locks, without any accident having hitherto occurred. Mr. Parkes observed that, independent of the advantages of carrying more passengers, by continuing the midship section to the length of 60 feet, considerable speed was gained by the 80 feet boat, in consequence of its fine entrance and run. Mr. Williams informed him that the velocity was found to depend on the position of the boat on the wave; that the rider of the horses employed in towing the boat knew exactly the proper position of the wave with respect to the boat, and regulated the exertion of the horses accordingly-the velocity of the boat and the tractive force depending on the relative position of the boat and wave. Mr. Field, in reply to some remarks respecting the effect of these rising ends on the buoyancy of the boat, stated that he did not understand it to be Mr. Williams' design to obtain additional buoyancy thereby. The ends only press on the water as much as is due to their own weight, and are principally useful in giving a fine entrance and run to the boat; thus having the whole space between the rising ends for the accommodation of passengers, and obtaining an absolute gain of the whole space that is lifted at each end, as in a boat of the ordinary length there must be the same tapering of the bow and stern ends. So great is the facility in managing the ends, that on quitting a lock the bow end is lowered as the gates are opening; the boat is set in motion at the same time, and as it moves on the stern end is let down, and the usual speed is obtained very soon after it clears the lock. When a lock is to be entered, the boat is suffered nearly to reach the gate at full speed, when the bow end being raised, the additional resistance, caused by the square section being suddenly opposed to the water, stops the boat almost immediately. The weight of one man, at each end, is amply sufficient to keep down the ends when the boat is in motion. "On the experiments and results of Mr. W. J. Henwood, as to; the power of the Huel Towan Engine." By George Woods. In this communication, the author refers to the experiments of Mr. Henwood, published in the second volume of the Transactions, and to the result there stated, that the curve traced by the pencil of the indicator during the expansion of the steam, deviates from a true parabola, according to the temperature of the medium contained in the jacket. Mr. Woods comes to the conclusion that, the temperature remaining constant, the curve will deviate very considerably from a true parabola. The results obtained by the author, as to the relative powers of the engine before and after the steam is cut off, and the mean pressure as given by the indicator diagram, do not differ materially from those given by Mr. Henwood. But Mr. Woods differs from Mr. Henwood as to that portion of the curve which the latter selects as representing the true value of expansive working. "Description of a Running Gauge for ascertaining the Parallelism of a Railway." By Edward Cowper. The construction of this guage somewhat resembles that of a truck, having two grooved wheels made to fit the rails on which it travels. It has two axles, one of them fixed and the other moveable, so as to accommodate itself to any variation in the width between the rails: to the end of the moveable axle is attached an arm, which, by its vibration across a dial, points out the degree of irregularity in the parallelism of the lines of rails. It can be used by hand, or attached to the end of a train of carriages, and is intended as a rapid mode of detecting any irregularity in the railway. "An Azimuth Cap as an addition to the common Level.” By Edward Cowper. า It is sometimes desirable in levelling operations to ascertain the bearing of objects which are either above or below the field of view of the telescope. The common level alone cannot take |