Steam-Engine — Physics, ^i-c 161 



in the United States, instances are not wanting of the suc- 

 cessful operation of high steam ; of which the engine at the 

 mint is a conspicuous example. There can, indeed, be no 

 good reason why this great power should not be employed to 

 an extent within the limits of safety, if more economical and 

 convenient. If boilers can bear (as they are usually made of 

 iron) 500 pounds, there can be no danger in using them with 

 fifty ; and this gives an increase of power, with a condenser, 

 fourfold, or makes a ten horse power forty. The economy, 

 therefore, of high steam, hardly admits of a question. It 

 seems unphilosophical to neglect a power so great, merely 

 because it is so. 



Mr. Watt was desirous of an improvement by which to 

 obtain a direct rotatory motion. His experiments, resembling 

 those of Curtis, at New-York, were not found permanently 

 practicable. 



It was probably perceived to be a great object to get rid of 

 a reciprocating movement of large masses, on the vvell-known 

 mechanical principle, that it consumes power to check mo- 

 mentum, as well as to give it — to drag an inert mass into 

 motion rapidly, in opposite directions. And in engines for 

 navigation this is more disadvantageous than for land uses, as 

 the foundation of the engine cannot be perfectly substantial. 



An engine, therefore, that possesses the cylinder and other 

 members of Watt's engine, working with or without a con- 

 denser, at pleasure — having a rotatory movement — requiring no 

 ponderous balance-wheel — adapted to high steam — attended by 

 no inconvenience from the rapidity of its stroke or move- 

 ment — having no inert mass of machinery to move recipro- 

 cally — ^more powerful, proportionately, from its using steam 

 as strong as that in the boilei* — of a simple and durable con- 

 struction, and by a combination of two similar machines at- 

 tached to the same common intermediate axis, operating so as 

 to give nearly an equal power at every moment of its opera- 

 tion, seems to combine every thing desirable in an engine for 

 the purposes of navigation. Such appears to be the re\ Giv- 

 ing engine invented by Mr. Morey, 



