S/R WILLIAM SIEMENS, F.R.S. 417 



/// t/ie discussion of the Paper 



" ON FORCES AND STRAINS OF RECOIL CONSIDERED 

 WITH REFERENCE TO THE ELASTIC FIELD 

 GUN-CARRIAGE," by HENRY JOSEPH BUTTER, M. lust. 

 C.E., 



DR. SIEMENS * thoroughly agreed with the mathematical 

 proposition put forward by Professor Unwin, which, indeed, 

 admitted of no doubt. At the same time, as Mr. Cowper had 

 already pointed out, there were great deductions to be made. All 

 the friction had to go in reduction of recoil, and that friction must 

 necessarily be largest at the commencement of the action when the 

 charge was rammed tight home. Then, again, the friction of the 

 gun-carriage upon the ground might be very considerable, and 

 that had to go in reduction ; so that theory and practice, as 

 propounded, and so well argued by the author, seemed to agree 

 nearly enough for general acceptance. He should like to add a 

 word with regard to an observation from Mr. Cowper regarding 

 his connection with the question of hydraulic compressors. All 

 that Dr. Siemens could claim was the mere suggestion of hydraulic 

 compression for gun-carriages, and that had been gracefully 

 acknowledged by the then head of the department (Colonel 

 H. Clerk, R.A., F.R.S.), in a Paper, read about a year after 

 the suggestion was made, before the British Association. The 

 fact of his suggestion, however, in no way detracted from the 

 great merit due to the officers of Woolwich, and especially to 

 the author, for the thorough way in which the hydraulic pressure 

 had been worked out for stationary guns, and had been now 

 brought forward as applicable to field guns. He could not 

 help thinking that the term " elastic gun " was unfortunate, 

 because it gave a wrong idea. Although the author had ex- 

 plained that it meant only one portion of the elastic action 

 without the elastic rebound, it was essentially an inappropriate 



* Excerpt Minutes of Proceedings of the Institution of Civil Engineers. Vi.l. 

 LXVII. Session 1881-82, pp. 148, 149. 



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