( 262 ) 



13r and 38 "/„ KNO, to 13^.5 and 45% KNO, 



Consequently, there exists no pnre melting point but D is trans- 

 formed on heating- to 134°. 5 into KNOg solid -\- solution of 45 7o- 



All mixtures of 0—50 KNO, solidify at 131' to Ag, -f D, all 

 mixtures of 50— 100 KNO, at 134°.5 to conglomerates of D -f- K^. 

 The first named remain uneiianged on further cooling. The last 

 named ought to change at 126° into D -f- K„ but this takes place 

 with great difücully. 



The double salt is also not readily formed. If it does not make 

 its appearance, the melting-point-line for K^ runs through to J 26°, 

 and below this Kj is converted into K., much more readily than in 

 the solid conglomerates. The melling-line of K„ runs through to 

 120° at 42 7o KNO, where it meets the prolongation of the melting 

 line of Ag.,. If I) does not appear, nJ/ liquid mixtui-es solidify at 

 120' to a conglomerate of Ag^ -f K^. 



The following zones comprised between the full lines represent 

 stable conditions 



i Ag, + L 4 L + K^ 



2 Ag, -i-L 5 L-i-D 



3 Ag, -fD 6 D + K, 



7 D -f K._^ 



All metastable boundaries are indicated bv dotted lines. The regions 

 concerned mav be easily deduced from the figure. 



From the above it follows that at the ordinary tempei-ature, only 

 the simple salts in the forms which are stable at that temperature 

 and also the double salts 1 : 1 can occur as stable conditions; this 

 agrees with what Rktgeks has previously found for the products of 

 crystallisation from aqueous solutions at 15*^. 



Chemistry. — "The transfonnation of beiizkliiie'\ By Prof. A. F. 

 HoLLEMAN and J. Potter van Loox. 



(Communicated iii the meeting of September :26, 1903). 



In the report of the meeting of this section of Nov. 20, '02 there 

 will be found a preliminary communication as to the experiments 

 conducted in my laboratory by Dr. J. Pottek van Loox, who has 

 since brought his research to a close. His results are briefly described 

 below. 



The methotl by which he succeeded in obtaining benzidine and 

 hydrazobenzene in a perfectly pu]'e condition has ali*eady been gi\'en 

 in the preliminary communication. In connection with this it may 

 be mentioned that hydrazobenzene w^as separated as a snow-^vhite 



