142 



HORIZONTAL FORCE MINIMA. OCCURRENCES. 



SSJSSS2S 



SSSSSSS2" 



2 3 



" " 



:: i ?i 



I I 



n ^ M 



| 



I I 



N -t N 



I I I 



S 3 * 



o u: 



M o ** o 



1 1 1 



1 - 



-( 



1 1 1 1 1 1 1 1 1 1 



lllllll 



O O O O 



1 1 1 



-> O C* O 



1 1 1 



1 1 1 1 1 



O 



1 1 



-t O O 



1 1 1 1 1 1 1 1 1 1 



H ^-* O 



1 1 1 1 I 1 1 1 1 1 



O O O O 



co <^ o 



- " 1 I 1 



w to oo 



i i i i 



00 t- H. W 



* 



00 N* 



Pi rH ^H 



91 * 



OJ O <O 



- 



^ i 



| 1 



-i w .-i 



- .-; 



! 





I MJ 



1 I I I 

 & t o 8 



5 S5 Q 







! l 



i^l 



H *9 M 







I s I 



1 5 g 

 S 2. S 

 1 (I 1 



