1010 



THAySACTIOXS OF THE AmERICAX INSTITUTE. 



Table showing Projyortion of j»?o?/j6'7' lost to overcome the Back 

 Pressure in Non-condensing Engines^ icorking icith the differen 

 steam pressiires named. 



The above table explains itself, and shows at once that the savings 

 due to an increase of steam pressure are important up to, say ninety 

 or 100 poundi. Abov^e that point, however, they are too wnall, in 

 his opinion, to overcome the well known disadvantages due to high 

 steam. There is a saving only of seven per cent by increasing the 

 pressure from ninety to 195 pounds, M'hich will hardly equal the 

 losses due to increased leakages, radiation, strain on the boiler, etc., 

 to say nothing of the popular feeling of greater danger. By still 

 further raising the pressure to 300 pounds, the increased saving 

 would be only 2.4 per cent. On the contrarj'-, it will be seen tliat 

 carrying less than eight}^ pounds steam pressure in a non-condensing 

 engine, as is too much the practice about this city, is simply throwing 

 away fuel. By careful experiment he found that the best practical 

 results are obtained with pressures varying between eighty and 100 

 poimds, and he considered that higher pressures are of advantage 

 only where light weight is of paramount importance. 



