22 ANNUAL OF SCIENTIFIC DISCOVERY. 



INTRODUCTION OP OSCILLATING ENGINES INTO LARGE AMERICAN 



MARINE STEAMERS. 



DURING the past year two of the largest American sea-steamers have 

 been fitted for the iirst time with oscillating, instead of beam engines. 

 Oscillating engines have been used in large vessels of the British and 

 French navy, for some time, with good success; but engines of this 

 character have not hitherto been applied to large vessels in this country. 

 The Golden Gate and Illinois, California steamers, have, during the 

 past summer, been supplied with this form of engine. The advantages 

 of an oscillating over a beam engine are said to be these : less weight 

 of machinery, per horse-power, than in the beam or side-lever engine ; 

 they have fewer working parts, are less expensive in repairs, consume 

 less lubricating material : they are subject to less strain, nearly all of 

 which is direct, and not transverse and diagonal as in the beam, and 

 their pressure on the gudgeons, when in operation, half less, requiring 

 consequently less strength and weight in the bed plates, and in the 

 timbers that sustain them, and they, together with their boilers, occupy 

 but fiive eighths of the space of a beam engine of the same power. 

 These advantages when segregated may not be much to each item, but 

 they, in the aggregate, are very considerable and important. The dif- 

 ference in the weight of the engine and in the space occupied by them 

 are, however, two very important items, especially in ocean steamers. 

 The former, in an engine of seven hundred nominal horse-power, is not 

 less than one hundred and fifty tons, one hundred of which is in mov- 

 able parts of the machinery, and the latter, as we have before stated, 

 is but five eighths of that required by the beam engines. 



In the engines of the Illinois, the air-cylinders are located between 

 the steam cylinders, directly over the condenser, and are worked by 

 piston rods connecting with the main shaft by a crank at its centre. 

 This centre-piece of the main shaft is wrought out of the heaviest piece 

 of iron ever forged in this country, and cost over seven thousand dol- 

 lars. Its journals are twenty-one inches in diameter. It was forged in 

 an entire block, and the crank cut out of the solid mass. The other 

 journals of the shaft are 19^ inches in diameter ; the crank pins are 

 12 inches, and the piston rods of the steam cylinders 12^ inches in di- 

 ameter. The cylinders are eighty-five inches in diameter, with nine 

 feet length of stroke. The diameter of the side wheels is thirty-three 

 and a half feet, length of float ten and a half, and depth two and a 

 half feet. In the trial trip of the Illinois, with twelve pounds of steam 

 to the inch, eighteen revolutions were accomplished, and a speed of 

 eighteen and a half miles to the hour obtained, running with the tide, 

 the velocity of which was about three and a half miles per hour, so 

 that the vessel moved through the water at the rate of about fifteen 

 miles an hour. 



STEAM POWER USED AT A DISTANCE. 



AN engine has been recently set to work at the Aucland colliery, ar- 

 ranged on a somewhat curious plan. The boiler is placed upon the 

 surface and the steam pipes are taken down the shaft, a depth of eighty 

 fathoms, and then down an inclined plane about 1,050 yards, making 



