( 556 ) 



220 iiiur. of H^N ill 4.920 gi-. of X,H,, r = 0.38, y, = U.U)--). It 

 is iuiowii lliat oji dissolving ammonia in water the conductive power 

 is l)ut verv slightly increased. 



From ihc toi-egoing we may draw the conchisioii that, with regard 

 to its ionising j)o\ver, hydra/jne is comparal)le to water. 



As regards mixinres of hydrazine and water il may l)(M)hser\-ed that 

 on addition of water the conductive power at first decreases reaching 

 a minimum with a mixture of (50 mols. of H^O to iOO mols. N,H^ 

 (about 25 per cent of Il.,() and 75 per cent of N.,TI J tiien increasing 

 again. This minimum, tiierefoi-e, does not coi'respond with the com- 

 position N.^H, -}- 1I,,(>, or the so-called hy(h'ate. 



Utrecht — Aiiistrrddiii. Jainiar\- 1903. 



Chemistry. — " Tlw rclociti/ of transformation of ti-iltroinopJicnol- 

 hroinuK' into trtrahron)oj)h('n.ol." By Mr. A. H. .1. Uklzkh ^). (4*^ ' 

 Connnunication on inti-amolecular rearrangement, presented by 

 l^rof. ('. A. LoBKY j)H Bruvn). 



(ConinumicatL'd in Uie meoliiii^' ot I'Y'biuai-y :28, 1*.)0;}). 



i)F,M',i)iKT ^) found in 1879 that li*il)i'omopiienol brought into contact 

 with bromine water is capable of exclianging a foui-th hych'ogen 

 atom foi- bromine with formation of a tetrabromo-derivative. Tiie 

 study of this substance led him to the conclusion that one Pu'-atom 

 occupies a jieculiai' position in the molecule; it is, in fact, the cause 

 of a certain number of reactions in which that l>r-atom is readily 

 displaced. As moi-eovei' the new substance seemed to have lost 

 the character of a piienol as shown by its insolubility in alkalis, 

 Benedikt ga\e it the formuhi C'^ H^ Hr., . ( )l)r and the name oflribro- 

 mophenolbromine. Benkdikt also noticed that, when melted under 

 sulphuric acid, it passes into the already known isomeric tetrabromo- 

 phenol, a true phenol which no longer contains a loosely bound 

 Br-atom. 



In his first publication Benedikt looked upon this transformation 

 into tetrabromophenol not as an intramolecular displacement of atoms 

 but as a i)rocess takhig place between two mol.s of tribomophenol- 

 l)roinine; in a later commuiucation liowever he does so, without 

 stating any reasons. 



When a few vears ago, Joh. Thikle ^) found that Benedikt's 



1) Proc. 31 May, 28 June and 2b Oct. 1902. 

 "') Annalen 199. 127, Monalshcfte 1. 301. 

 •") Ber. 33. Ü73 (1900). 



