MECHANICS AND USEFUL ARTS. 45 



the most durable material for an igniter, and that a continual circulation of 

 water through the piston-rod and around the cylinder is considered the best 

 method of disposing of the surplus heat, which would otherwise destroy first 

 the lubricating material, and next the metal itself. 



Pendidoits Reciprocating Steam Engine. A novel and cheap engine has 

 recently been invented with the above title. It is an " eccentric revolving on 

 its own diameter" in a "cylinder," or steam-chamber, suspended as a pendu- 

 lum, the shaft on which the eccentric piston is keyed being the main or driv- 

 ing shaft, and makes upward of 100 revolutions per minute in a 30-horse 

 engine. The principle of this is similar to the ordinary engine, but it works 

 with much less friction ; a 30-horse high -pressure will work with one pound 

 of steam. "An eccentric revolving on its own diameter" contains the two 

 motions of the ordinary engine, viz., rectilinear and revolving, though so 

 amalgamated as to be hardly distinguishable. This engine, from the small 

 space it occupies, and the speed that can be obtained direct, is especially 

 adapted for screw propulsion. 



Pattisorfs Improved Oscillating Engine. The principle peculiarity of this 

 engine is, that it does not, as in ordinary oscillators, admit steam at the trun- 

 nions, but takes it in through an arched pipe surmounting and secured to the 

 cylinder. As the cylinder oscillates on its trunnions, it simultaneously brings 

 the induction and exhaust ports into communication with the steam ports in 

 the wings or flanges of the saddle which fits over the arched steam-pipe. 

 By thus receiving the steam, friction is saved, the motion is left freer, and 

 there is also, of course, a diminution of wear and tear. Its arrangements, 

 also, render it more promptly reversible than any other engine which we have 

 yet seen. The same lever and eccentric rod, by which the motion is reversed 

 affects the cut-off valve. The cut-off valve, besides serving to stop, to reverse, 

 and to cut off the steam, answers the purpose of an exhaust pipe as well. 

 The cylinder lies in a horizontal position ; and the saddle, which fits over the 

 arched pipe to which we have referred, is so constructed as to rest on adjust- 

 able screws, allowing the saddle to accommodate itself to the motion of the 

 cylinder, etc., etc. The engine is alike adaptable and equally efficient for 

 locomotive, standing, or marine purposes. 



Improved Locomotive Boiler. A new form of boiler has recently been tried 

 in its application to locomotives, hi England, with great economy in fuel, and 

 time it is said in getting up steam. The improvement consists hi piercing 

 the sides and top of the fire-box, and the crown plate of the boiler flue, 

 with a number of holes about three inches diameter, into each of which, pro- 

 jecting into the water space, is riveted a malleable cast-iron cup, from four to 

 six niches deep, those on the sides being cylindrical, while those on the crown 

 plate are spherical. These cups are, of course, covered in every direction by 

 the water in the boiler, and the inside being exposed to the heat of the fire 

 and concentrating the temperature, present so much additional heating sur- 

 face, that the boiler is enabled to get up steam in a vast deal less time, with a 

 diminished quantity of fuel. 



At the Boston locomotive works, a twenty-two ton passenger locomotive 

 has been recently constructed on an entirely novel principle. For the gener- 



