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Art. VIII. Description of Mr. Rider's Rotatory Steam- 

 Engine. (With a Plate.) 



[To the Editor of the Quarterly Journal of Science.] 



Belfast, August 27, 1823. 



Sir, 



A variety of occurrences have, until now, induced me to de- 

 cline publishing on the subject of my rotatory steam-engines. My 

 principal reason was, that I did not wish to appear before the pub- 

 lic until the matter, from actual experience, and deliberate trial, was 

 placed beyond a doubt of success. I feel the greater satisfaction 

 in informing you that I consider this desirable object is now at- 

 tained, there being three engines on my principle at present work- 

 ing at different places in this neighbourhood with the greatest 

 success, one of which is twelve, one sixteen, and the other twenty 

 horse power. 



I send you herewith drawings, and a description of my rotatory 

 engine, through my friend Mr. Boyd ; and should you still enter- 

 tain the same favourable opinion of the improvement, which you 

 were pleased to express to him, I shall feel much obliged by your 

 taking such notice of it as you think it deserves, in the Journal 

 which you conduct. 



The advantages which these engines possess, are, that they 

 require less room, less weight, consume less fuel, and are cheaper 

 than the common engine ; beside the expense of foundation work, 

 and buildings necessary for erection, is considerably reduced. 



By this important improvement, so long sought after, the opera- 

 tion of the steam on the piston, from its first action, is completely 

 uniform, and may be communicated to any purpose required, with- 

 out the loss of power occasioned by the use of lever beams, crosses, 

 cranks, fly wheels, or balances of any description. 



For steam navigation these engines are peculiarly adapted, 

 where the saving of room and weight is an object of much im- 

 portance. 



