50 



THE ATOMIC WEIGHTS OF 



to 11.043. Hence it must be inferred that the author rejected 

 a number of analyses. The chloride was analyzed in a similar 

 way. 



These remarks suffice to indicate that the binary compounds 

 of boron have not yet been analyzed with sufficient accuracy for 

 atomic weight purposes. To this end a reinvestigation of the 

 halides of boron would seem desirable and in such an investigation 

 the more recent work of A. Stock et al. 5 might prove of great 

 value, according to whom certain substituted hydrides of boron 

 (e.g., B 2 H 5 Br) must be regarded as analogues of the corresponding 

 derivatives of carbon and hence seem to involve quadrivalent 

 boron. On the other hand, boron appears to be strictly trivalent 



TABLE 4. The atomic weighl of boron derived from previous analyses of borax. 



i Fogg. Ann. 2, 129, 8, 19. 



Compt. rend. 29, 5. 



Quoted by Brauner in Abe gg'a " Handbuch, 



etc.," Vol. Ill, 1, p. 6 (1906). 

 <Jour. Chem. Soc. 61, 650-666 (1892), 



(edited by Ewan and Hartog.) 



6 Ibid. 63, 211-217 (1893). 



6 Chem. N. 77, 78 (1898) ; see also Brauner, 



op. cit., p. 8, 9. 

 7 Ber. 26, 164-171 (1893). 

 8 See note on p. 59 



A. Stock and O. Priess, Ber. 47, 3109-13 (1914), and a number of other papers; see 

 also reference on p. iii. 



