-1s R is added to .1,the vapor-pressure of -4 decreases in sa>.according to curve nc. At c, which is soiiie cersome v-a>-> tain point s-ar!,iiig n-ith the iiiixtiire and the temperature, another phase appears, for the liquids are not il-riscible in all proportions. On further addition of E,this new phase increases at the cost of the first phase. On continued addition of B the first phase finally disappears eiitirel!: T h e vapor-pressure of *1in the two phases is the same, lint the quantity of 13 in the new phase is greater than in the first phase. Consequentl>-,the composition of the new phase is represented b!. d to the right of c and on a level n-ith it. On farther addition of B we get tlie unbroken curve d R for the 1-apor-pressure of in tlie mixture after the first pliase has disappeared. Siiiiilarly, when is added to 13, the 1-aporpressure curve of R is hefA4. I t is evident that c aiidflie on the same ordinate and that c and d likewise lie on the same ordinate. Had a new phase not appeared at all, the vapor-pressnre of -1i n a mixture correspoiidiiig to the composition denoted b y d nould 1iai.e been g i : R u t as the second phase clisappears, the 1-apor-pressure of -1in the second phase is greater than gi. Hence I3 in the second phase has a molecular weight greater than R in the first phase has. So tlie separatioii of a second phase in a mixture of liquids shon-s the sndden forination of more complex niolecnles on the part of one constituent. Similarly, when is added to B. I t \voald seem therefore that when two phases are formed in a liquid mixture, a sudden increase in the molecular weight of each constitueiit is indicated. Curve nJ’X.6 is the vapor-press i r e ciirve of a mixture whose constituents have the x-apor-pressine curves considered above. Rzdgem College, .7Jui,ch 26, zS9S
