( 181 ) 



decrease of pressure is deposited in crystals. Paraffine strongly dissolves 

 in aethjlene ; so much so that under a pressure of 150 atniosplicros 

 we can make it evaporate nUondhcr. Stearine acid also easily dis- 

 solves in aethylene, hut nol to such a high degree as i)a)'affine. 



As yet we have iu)t been able to explain the total evaporation of 

 a solid by a gas above its critical state, irithoiit an iMcrnwdinfc 

 //(/ii/(/ phast'; this is owing to the fact, that there was no sns|»ici(»ii 

 of the behaxionr sho\vn by the system ether and anthrachiiion. If 

 '(Ve compare the figures 3 and 4 with each other, it is obvions that 

 if in tig. 3 we start from solid B and by compression of A at a 

 constant temj)erature we follow a course ])arallel to the ,/'-axis from 

 right to left, a liquid phase will always ap[)ear first before we 

 come into the gas-region. This i)lienomenon observed by A'illakd 

 in llie system camphor-aethylene will also occur in fig. 4 i)etween 

 the temperatures /^ and t.^ and betw^een t.^ and /,, so that this be- 

 haviour does not decide the type to which the system belongs. 

 Investigations at different temperatures oidy would enable us to do so. 



It is, how^ever, quite different, when the solid evaporates altogetlier 

 without giving a liqnid first. If this be the case Ave can directly 

 point out the type; then it belongs namely to type fig. 4, for there 

 on])/ it is j)ossil)le /nheii eomijKj from the ri'ijio]} for solid ]j-\-ni jtoin' 

 to pass into the (i<is-region uiitliout an iiiti'rine'tiuti' rHjiiid-phase, as 

 hnn/ as nv worl' ttetweeii the temperatures t.^ and /„. 



Probably the systems alcohol + KI, KP>r, Ca CI, and ('S., -[- 1, ot 

 Hannay and Hogarth, ether-[-HgI._j of Wood and ('().^-|-l,, of \'im,\i{|) 

 belong for the greater })art to the type fig. 4. 



That, as would follow from Yillard's experiments, also the partial 

 vapour tension of solids would be considerably inci-ensed by relat- 

 ively slight pressures (I()() a 200 atmospheres) of an additional gas, 

 seems, however, possible to me only wIhmi the vaponi'-line of the 

 system solid-vapour can get a course similar to that of li(piid-\apoiir, 

 which will probably be the case only when the added gas .1 dissolves 

 in the solid phase Jj. This point will soon be investigated by me. 



Chemieal /(dioj-atari/ of the ( 'j/irersifi/. 



Amst('rdan/, Septembei- 11>03. 



