TRANSACTIONS OF SECTION B. 665 



This behaviour of dichloro urea with alkalis afi'ords an insight into what 

 occurs when urea is decomposed either by an excess of alkaline hypochlorite or 

 hypobromite. The course of this reaction has never hitherto been explained, 

 although it has received an unusual amount of attention on account of its fur- 

 nishing .1 ready nethod of estimating the quantity of urea present in a liquid. In 

 this reaction the urea is without doubt converted into a chloro or bromo urea, 

 which is at once hydrolysed in the manner above described. It is possible that 

 in presence of excess of hypochlorite or hypobromite a tri- or tetra-substitution 

 product may be produced, the formation and decomposition of which can be formu- 

 lated easily, but this does not affect the essential character of the reaction, which 

 is one of halogen substitution followed by hydrolysis of the substituted urea and 

 interaction between the resulting compounds. 



A reaction which indicates the use to which dichloro urea may be put in the 

 synthesis of simple carbon and nitrogen rings is that between it and ammonia. 



When ammonia in excess is added to an aqueous solution of dichloro urea, 

 hydrolysis, accompanied by liberation of nitrogen and formation of carbonate, 



occurs, but in addition diurea COy-j^jj j^jjyCO is produced, and separates 



in considerable quantity as a sparingly soluble crystalline powder. This is the 

 first direct synthesis of diurea from urea itself, the compound having been pre- 

 viously obtained from ethyl carbonate and hydrazine. 



This adds another to the very few reactions known by which nitrogen atoms 

 can be made to link up together, and further affords an exceedingly simple 

 synthesis of hydrazine. 



Diurea, when heated with excess of strong sulphuric acid to a little above 

 1C0° 0., is easily hydrolysed, carbon dioxide escapes, and hydrazine sulphate is 

 produced. This crystallises out perfectly pure in almost theoretical amount on 

 cooling and adding a little water. 



Dichloro urea can be prepared from urea and converted into diurea so easily, 

 and the latter can be hydrolysed so quickly, that the reactions afford a synthesis 

 of hydrazine more adapted to prepare a small quantity than any yet described. 

 The operations involved are so simple and can be carried out so quickly, that they 

 are also excellently juitecl for showing the synthesis of hydrazine as a lecture 

 experiment. 



8. Re^iort on Dynamic Isomerism. — See Reports, p. 112. 



FBIDAY, SEPTEMBER 4. 



Discussion on the Nature of Chemical Change. Opened by Professor 

 H. E. Armstrong, F.B.S. 



The following Papers were then read : — 



1 . Ifote on a Volatile Compound of Cobalt with Carbon Monoxide. By 

 Dr. LuDwiG MoND, F.R.S., Dr. Heinrich Hirtz, and M. Dalton 



COWAP. 



In a previous paper,' published by one of us in conjunction with Dr. Carl 

 Langer and Dr. F. Quincke, entitled ' Action of Carbon Monoxide on Nickel,' p. 752, 

 we stated that ' numerous experiments made to obtain similar compounds of 



' Journal of the Chemical Society, 1890, p. 749. 



