All About Engines

x34 All About Engines siderable. Thus, the weight of a 12-inch diameter solid piston would be about 75 lb., and this only a small one ; the weight of the connecting rod would be another 75 lb. ; and so on. And this measures the increase of friction on the lower half of the cylinder liner and gland, and the lower cross-head guide. On the other hand, in a vertical engine all the sliding surfaces are vertical, and there is no excessive fric- tion arising from the weight of the parts themselves. In any quick revolution engine, moreover, the steam is for a shorter time in contact with the cylinder walls and is, consequently, less subject to condensa- tion. If you were to ask the advocate of horizontal engines about these matters he would probably say that the obj ections are theoretical rather than practi- cal, and that with the excellent materials available to- day the extra wear is infinitesimal. And the advocate of vertical engines would reply that, nevertheless, the friction is increased and the wear takes place. The man who believes in horizontal engines will probably point out that though the friction in a vertical engine may be less, the piston and moving parts have to be lifted and then allowed to fall every revolution, and that the lift has to take place when the steam is act- ing on the smaller area on the piston-rod side, while in his engine the moving parts remain at the same level. And in return he may be asked whether he can detect the faintest irregularity in a well-made modern vertical engine. While there are doubtless good reasons why