40 



NOTES ON STATIONARY ENGINES. 



is no question as to some points of superiority, and even 

 indirectly of simplicity in a high-speed engine. In the first 

 place, a amallor and more compact engine will do the work 

 afc a high speed; sticondly, it l)(M3()m(!s ])r:u!(.ical)lo to adopt a 

 higher grade of expansion witliont reooursc to the com- 

 pound principle. It will also be found that the running is 

 more uniform in Iiigh-speed engines than in low-speed ones. 

 It need not be feared that a high-speed engine will " knock 

 itself to pieces " with groat rapidity if well designed and 

 constructed. If, however, any one sets up a high-speed 

 engine, relying upon its smaller size for a lower cost, ho will 

 find himself wof ully mistaken. All mach inery to be di'iven at 

 a high spcodmust he throughout of the most unoxcoptionablo 

 quality, or its utter and complete collapse is certain; but 

 granting this condition, its life is almost everlasting. Tlie 

 Allen engine of twenty years ago furnishes a case in point. 

 It was introduced into this country by Mr. 0. T. Porter, an 

 engineer of the fiirst order, who hold that no part of an 

 engine should wear out if properly designed ; this, though 

 not absolutely sustained in practice, has been go nearly ap- 

 proached as to raise hopes that perhaps at some time in the 

 future it may be realised. Two of these engines were working 

 for years, often up to ono hundred hours per week, and witli 

 comparatively little trouble, and another had the scraping 

 marks under the crosshead as plainly visible after ten years' 

 work as they were on the day they left the shop. All these 

 engines were working at 1,000 feet piston speed per minute, 

 which is about the extreme reached in locomotive practice. 

 Previously to the advent of the Allen engine, the usual 

 speed in good practice for stationary engines was about 400 

 feet per minute. That the Allen engine did not meet with 

 a much better reception than was the case, is a point for the 

 most sincci'e regret, not only for the sake of the engine 



