44 NOTES ON STATIONARY ENGINES. 



being necessary when any great cliango is made in working 

 arrangements, and the opportunity is taken to give things a 

 most thorough ovorhanl ; the leading point in the project 

 then often gets the whole credit, even when (as is the case 

 occasionally) in itself it may be worse than valueless. 



In conclusion, it may be pointed out that in the beam 

 engine the cylinder stands vortical, with the piston rod out 

 at the top; then in course of time this is displaced by tlio 

 horizontal form, with the piston rod out at the end ; and if 

 it were not dangerous to " prophesy, except you know," it 

 might be predicted that in the coarse of a few more years 

 the ruling typo for engines for rotative driving will be the 

 vertical inverted, with the piston rod out at the bottom. 

 This type presents several points of convenience. The 

 craidi shaft, be it over so well balanced, still requires a good 

 deal of steadying, and in the vortical inverted engine this 

 can be done with the utmost facility and security. Then 

 the whole of the str'ains are as a rail! vertical, and therefore 

 there is no excuse for elaborately divided brasses to carry 

 the crank shaft. The floor space is less in these engines 

 than in any other ; and if there is any difference between 

 the types in steadiness in driving, the vertical inverted 

 engine will not suffer in the comparison. One other point 

 may be suggested in connection with the engine of the 

 futui'o, v'vA., that the crosshead slides will bo a thing of 

 the past, and that a pai'allol motion will bo adopted in 

 its place. In the present marine engine there is a very 

 important first instalment towards the parallel motion, 

 in the form of the pr-eserit pump lovers, which would form 

 part of such motion with a little modification. Perhaps 

 after this the revolving wheel of fashion will again bring 

 round the beam engine and the horizontal engine to dis- 

 place the vertical inverted type, but at all events such is 

 not the opinion held by your humble servant. 



