( 613 ) 



and (NH 4 ) 2 S0 4 and ii is evident that two cases may occur. It m.iv 

 be that the two liquids contain the two components in the same propor- 

 tion as they occur In the double salt; it is then as if' the double 

 salt dissolves in both liquids without decomposition. It' this is the 

 case the liquids c, and c, will be in equilibrium with each other. 



The second possibility is that one of the liquids has in regard to 

 the double salt an excess of Li s S0 4 and (he olher, therefore, an 

 excess of (NH 4 ) 3 S0 4 ; in this case, c, and c a cannot be in equilibrium 

 with each other. The experiment now shows such to be the case. 

 When I saturated a water-alcohol mixture with LiNH 4 SO at 50°, 

 the alcoholic layer contained a small excess of Li 8 S0 4 and the aqueous 

 layer a small excess of (NH 4 ) 2 S0 4 . From this it follows that the 

 conjugation line does not coincide with the surface DA IV but intersects 

 it; the part to the right of the line must be situated in front of the 

 plane and the left part behind it. The alcoholic solution c a of the 

 double salt cannot, therefore, be in equilibrium with the aqueous 

 solution c l of this double salt, bat may be so with a solution con- 

 taining an excess of (NH 4 ),S0 4 . 



Chemistry. "On catalytic reactions connected with the transformation 

 of yellow phosphorus into the red modification." By Dr. .1. 

 Böeseken. (Communicated by Prof. A. F. Holleman). 



(Communicated in the meeting of January 26, 1907). 



From the researches of Hittorf (Pogg. Ann. 126 pag. 193) 

 Lemoine (Ann. Oh. Ph. [4] 24. 129) Troost and Hauteeeuille (Ann. 

 Ch. Ph. [5] 2 pag. 153), R. Schenck (B. Ch. G. 1902 p. 351 and 

 1903 p. 970) and the treatises of Naimann (B. Ch. G. 187 2p. 646), 

 Schaum (Lieb. Ann. 1898. 300 p. 221), Wegscheider and Kaufler 

 (Cent. Blatt 1901 I p. 1035) and Roozeboom (Das heterogene Gleich- 

 gewicht I p. 171 and 177) it appears highly probable that red phos- 

 phorus is a polymer of the yellow variety, which polymerism is, 

 however, restricted exclusively to the liquid and the solid conditions : 

 the vapour (below 1000°) always consists of the monomer P 4 . 



From the above considerations it moreover follows that the yellow 

 phosphorus is metastable at all temperatures below the melting point 

 of the red phosphorus (630°); it may, therefore, be expected that 

 it will endeavour to pass into the red variety below 630°. 



