( 383 ) 



As is also sliowu in the ttihle 



&' z:zz b(J tij .nit iO ttj a 



ooc'Oines 



jr 



for ./; = 0, « <^ - CMjiuil to 0, 



Jt 

 for .r = 0, a =1 indefinite, and 



foi « = also Q\Qv\ time 0, wliilst 



— 8" = Ixj 1g sin X cot a 

 for ./• = 0. (t^ equal to 0, 

 for ,/; = 0, a == indefinite, and lastly 



rr 



for «= always Uceoines 0. 



2 



In ordei- to know the extinction of the plane (JV) with respect to 

 the Irace of ;/'((JIÜ) or A' (100), we combine this table with table TI. 



26 



Proceedings Royal Acad. Amsterdam. Vol. X. 



