349 



whirli Wisi.icKNuy ') h.-id discovered two modifications a few years 

 before, viz. the solid hdo and the liquid i'uol compound. 



Of late a number of investigations on other substances with inter- 

 molecular tran.sforination have been published by Dimkoth "). These 

 very interesting publications tieat molecular conversions in derivatives 

 of Iriazol, in different solvents. 



One of the isomers is always an acid which can be determined 

 titrimelrically, which may be called a very favourable circumstance 

 for the study of the 'phenomena of conversion. 



Another substance whose peculiar behaviour has already induced 

 many investigators to occupy themselves with it, is the /n/drazoii of 

 dcetaldehydi', of which Fischer') discovered two moditications. 



Bamberger and Pemsel*) undertook a further investigation, a few 

 years later also Lockemann and Liesche*), and six years later Laws 

 and SiDCiWiOK"), but none of these investigators has succeeded in 

 unravelling the behaviour of this peculiar substance. 



P. nitrobi'nzal-[jheayl-iin'tluil-hiidrazon,, investigated by Backer") is 

 another hydrazon which shows great resemblance with the former. 

 Also this substance possesses, two moditications, a red and a yellow 

 one, but it is not known as yet, in what relation the,se forms are 

 to each otiiei-. 



The .system iireuiii-(t)intiouiuiiici/(inat(', further e.xamincd by Walker 

 and Hambi.y '), just as the system siil iiho-uri'um-aimiiovbi in.ml phocijniDttt' 

 studied by Voi.hakd') Waduei.i, '"), Reynolds and Wki{ner ''), Find- 

 lay'^), and tinally by Smits and Kettnek '•''). likewise belong to the 

 organic pseudo-systems, just as ci/aiiO(/c'ii-/>iiri(ci/im(i(j(m investigated 

 by Terwen '■') and ci/auoijeiuchi/droi/eii.ic acid, cyaairic acid and 

 cyamelide investigated by Troost and Hautefeuille'^}. 



1) Ber. 20, 2933 (18h'7); 28, 767 (1S95), 



2) Ber. 35, 4041 (I'M"!); Lieb. Ann 335, 1 (l'JU4); 338, 143 (19U5), 364,183 

 (1909); 373, 336 (1910), 377, 127 (-1910). 



8) Ber. 29, 795 (1896). 



4) Ber. 36, ^5 (1903) 



5) Lieb. Ann. 342, 14 (1905). 



6) Journ. Ghem. Soc. 99, 208.j (1911). 

 ") Dissertation, Leicleu 1911. 



8) Journ. chem. Soc. 67, 740 (1895). 



9) Ber. 7, 92 (1874). 



W) Journ. phys. chem. 2, 525 (1898). 



11) Journ. chem. Soc: 83, 1 (1903). 



12) Journ. chem. Soc. 85, 403 (1904). 

 IS) These Proc. Vol. 15, p. 683 (1912). 

 1') Dissertation Amsterdam 1913. 



1») Gompt. rend 66, 795; 67, 1345. 



