134 



8. Witli a complex of (he 7i^^ order, T", the complex j?-| of the 

 tangents lias a couiirufvce (2?j, 2?i) in common which has for image 

 a null system N (ii, 2ii). /'" has 2n straigiit lines in common with 

 any scroll of H, hence the null system \\&sAin singular straigid lines. 

 In of which pass through _S, and 2n through B^. B^ and B^ are 

 therefore singular null points. The straight line b is evidently a 

 singular mill ray. 



