192 APPENDIX I. 



The existence of k equations of the first degree between n 

 motors is the condition of their belonging to a screw complex 

 of the first degree, and of order n - k. 



EVERETT (J. D.) On a new method in Statics and Kinematics. 

 (Part II.) Messenger of Mathematics. New Series.. 

 No. 45 (1875). 



This paper contains further developments of the theory of 

 linear relations between motors. Several of the leading theorems 

 in screws are directly deduced from motor equations by the 

 ordinary rules of determinants. 



EVERETT (J. D.) On a new method in Statics and Kinematics. 



(Part III.) Messenger of Mathematics. New Series. 



No. 53 (i8?5). 



This paper is devoted to the operation of motors upon 

 motors. The interpretation of such operations is given, the 

 laws of operation are laid down, and some applications are made, 

 involving the use of a special symbol called a " motor de- 

 terminant." 



