

On 



Quaternionic Relativity. 



Load. 



Tan y. 



7- 



Temp. 



5-68 i 



rrauis. 



0-36 + -01 



20° + 30' 



-5° 65 C. 



10-39 



>> 



ii ii 



ii ii 



-5° -65 



1196 



ii 



i» ii 



ii >i 



-5°-75 



12-74 



»> 



ii i» 



ii ii 



-5°-60 



1353 



»» 



ii ii 



ii ii 



-5°-65 



14-31 



»» 



1) !> 



»! 11 



-5° 65 



15-10 





0-17+ -01 



9°-30'+30' 



-5°-60 



16-67 



ii 



ii ii 



ii ii 



-5° -55 



19-81 



i> 



ii it 



n ii 



-5°-60 



24-52 



ii 



ii i> 



ii ii 



-5°-60 



5-68 



>i 



0-36 ±'01 



20° ± 30' 



-5° -60 



135 



These experiments were repeated on another occasion with 

 the same result and similar results had been obtained with 

 different apparatus. 



As a result of the investigation the following points are 

 clearly shown : — 



(1) The coefficient of friction for ice at constant tem- 

 perature may have either of two constant values according 

 to the pressure per unit surface of contact. 



(2) For small pressures, and up to a certain well defined 

 limit of pressure, the coefficient is fairly large, having the 

 value 0*36 ±01 in the case investigated. 



(3) For pressures greater than the above limit the co- 

 efficient is relatively small, having the value 0*17 + '01 in the 

 case investigated. 



In conclusion it remains for the writer to express his 

 thanks to Dr. Joly both for suggesting the work and also for 

 his kind interest during its progress. 



The Physical Laboratory, 

 Trinity College, Dublin. 

 Nov. 13, 1912. 



XIV. Second Memoir on Quaternionic Relativity, By L. 

 Silberstein, Ph.D., University Lecturer in Natural 

 Philosophy, Rome *. 



IN my first paper on this subject f I developed the funda- 

 mental relativistic formulse in quaternionic language 

 along with their application to the system of differential 

 equations of the electron theory, and have given, finally, 



* Communicated by the Author. 



t Phil. Mag. vol. xxiii. May 1912 (written Nov. 1911). 



