GRAPHICAL ALGEBRA 



B 



1 2 J ( 6 7 a $ '0 II 12 13 



ft- a ~t(60) 

 B <p -a,'8(se) 



8 9 /O ?/ V 13 



8 



/3-a~/z(sz) 



1Z(SZ) 



8(S6) 



*m s ^L 



10 II IZ IJ 



to it a 



fi-a.-zofii) 



,S-a-2*(to) 



Fig. 78. Graphical tables for vector-addition. 



