42 



III conclusion it may still be mentioned 

 iliat the question vviiat place tliiee remark- 

 able "acid boric acid esters" described 

 by WoHi> and Neubk.hg ') and also the 

 boric acid complexes ') found by Gkun 

 and NossowiTCH, occupy in this respect 

 must still be made a subject of investi- 

 gation. 



I may still i)e allowed to express my great indebtedness to Prof. 

 BoKSKKEN for the kind interest which he evinced in this investiga- 

 tion carried out in his laboratory. 



Delft, December, 1922. (h-gnnic Lab. of the Technical Univ. 



') Ber 32, 3488 (1899). 



2) Sitz. Ber der Akad. der Wiss. Wien M. N. 01. 125, 2B, 171 (1916). 



