26 ANNUAL OF SCIENTIFIC DISCOVERY. 



at a speed of 80 miles an hour, with a large express train. The cylin- 

 ders are 16 inches diameter, and 22 inches stroke ; the driving wheels 

 6 feet in diameter, and the bearing wheels 39 inches ; the heating sur- 

 face of the firebox is 98 square feet ; the boiler is traversed by 158 

 brass tubes, giving a heating surface of 865 square feet. The principal 

 improvements claimed by Messrs. Hawthorn for this locomotive are the 

 following : Instead of the six ordinary springs on each axle, the engine 

 is fitted with double compensating beams and four springs acting simul- 

 taneously on all the journals, so that the weight assigned to the respect- 

 ive axles is not affected by any irregularities or imperfections on the 

 line of railway, but is uniformly maintained throughout, securing thereby 

 a constant weight upon the driving wheels, and consequently a constant 

 amount of adhesion. By this direct, simultaneous connexion between 

 the axles, great stability is given to the engine ; greater safety, particu- 

 larly at high speed ; and a smoother and easier motion. The engine 

 has outside framing, with outside bearings to all the axles, the cylinders 

 being placed inside ; it is supported on six wheels, the driving wheels 

 being in the centre. The second advantage claimed, is the application 

 of expansive link motion and slide valves, which admit of the boiler 

 being brought down nearly as low as in engines with straight axles ; 

 and, by the introduction of the slide valves, the pressure on the valves, 

 and consequently the friction, is considerably diminished. An arrange- 

 ment is likewise introduced into the engine of the patent steam-pipe of 

 Messrs. Hawthorn, which removes the domes and other projections on 

 the top of the boiler. The steam-pipe is fixed into the tube plate of the 

 smoke-box by a ferule like an ordinary tube, and extends nearly the 

 entire length of the boiler. Being carried under the top, it is perforated 

 with a series of small apertures or slits along its entire length, and it is 

 arranged so as to receive the steam directly above the place at which it 

 is generated, instead of compelling it to rush from all parts of the boiler 

 to one or two orifices. By this arrangement, the steam is conducted to 

 the cylinder, nearly, if not altogether, free from priming. 



NOVA MOTIVE. 



AT the Polytechnic Institution is a new mode of propulsion now 

 being demonstrated, which, under this title, consists of a series of car- 

 riages travelling along with their own motor, in the form of a tube, which 

 is flexible and air-tight. This tube has a series of side valves, entirely 

 under the care of a guard, who, by levers, has a perfect control over his 

 train. The application is very ingenious, and is the invention of a 

 mechanic. Along the whole line of railway is laid a pipe of any given 

 diameter, in connection with which a series of pistons are fixed between 

 the rails intended to receive the tube above mentioned in its passage. 

 In these pistons are atmospheric valves opening into the fixed pipe, 

 which is always kept exhausted, so that, when the train passes over 

 the pistons, the side valves in the tube are opened by means of inclined 

 planes communicating with other levers, which levers are raised up on 

 the train passing. The atmosphere existing in the tube consequently 

 rushes from the tube to supply the vacuum, and the train is impelled 

 by external atmospheric pressure. London Illustrated Neivs. 



