( 243 ) 



We denote then the latent Meat of li(|neftietion l)y P. and the 

 heat of evaporation l»y /■. 



liet the principal (*(iini)onent We anthracpiinone at its triple [»oint. If 

 we add a verv small qnantily of ether, ,/■.,. and ,/•/ and ,/,/ will l)e 

 small Init ',/ ^ 'V ^ '".s- We may even assume by approximation 

 for this case, that no ether passes into the solid phase; hai'dly 

 any will he found in the lirpiid, hut most of it in the vapour. So 



J', = {) and is verv fireat. For the limitin.u' case which ma\" he 



■'7 

 supposed, in which ,r/ would he zero, we have: 



dp X 



T -^- — 



<IT r/ — r. 



The initial direction of the /),T curve is that of the melting curve, 

 and when 'V ^ r.., this curve begins as an ascending cnrve with 

 increasing temperature. But as soon as after further addition of 



;i7 — d's VI — Vs 



ether the value of has become equal to , in which still a 



.t-(/— .f.s i^d—rs 



very small value of .t'/ is supposed, the luimerator of the expression 



for / — is intinitelv larue and on further addition the sign of the 

 dT 



numerator is reversed and the p/l' curve is no longer ascending, 



hut descending with increase of 7\ 



Now let ether lie the principal component. In this case we have 

 to distinguish two different cases. 1"^^ . Ether and anthraquinone are 

 in solid state miscible in all proportions ; then the solid substance 

 Avhich we must think present, is so/ifl ctlu'r and we start from the 

 triple point of ether. "2"'. For all equilibriums anthraquinone remains 

 unmixed with ether. Then the temperature nuist be thought slightly 

 above the triple point of ether. 



In the first case, if at the triple [)oijit of eiher a little of the 

 so much less volatile substance, anthi-acpnnone is added, it is to 

 be expected neither in the vapour, iu)r in the solid body, but only 

 in the liquid; then we find: 



dn r 4- ;. 



dT i\i—r. 



So an increase of p with T, as occurs iu the case of equilibrium 

 between vapour and solid, in concordance with the rule, that if 

 two phases of a mixture iu which moi-c phases are present, are of 

 the same concentration, the (^(piiliitriuui conforms to these two j)hases. 



In the second case, in which \vc liiink ether present iu li(pii(l 

 and vapour stale at slightly higher temperature than that of the 



