( 193 ) 



make their appejiniiico liere It is llicrofore not iniproh.il)!^ lliat 

 Calvert's doubt finds its origin in tliis circnnistancc. 



In the adjoined 7\V-fignre the lines Zjfd^ and h^e^ represent tiie 

 two parts of the nieUing-point line of phenol in the system water- 

 phenol, which are separated by the region of non-miscibility. 



Now the most remarkable thing in the system mentioned is this 

 that notwithstanding this part yd, appeared to be metastable, we 

 can just as easily determine this part as the part zy, because as a 

 rule it is exactly points of solidification of the part tjd^ that are 

 observed when water-j)lienol mixtures of concentrations corresponding 

 to this line are cooled without any precaution. 



So this must be the reason that Patkhno and Ampola found 

 exactly this line, or rather that they oidy got deposited solid phx'uol. 

 The melting-point curve they found, agrees, indeed, with the curve 

 zgd^ with regard to its shape, but on the whole they found lower 

 temperatures ; at some places the difference is even 1°. 



It is clear from the tig. that for concentrations lying between the 

 points r/j and h^ at a cei'tain temperature solid phenol must deposit 

 from the two layer system, whereas the acjueous liquid layer nuist 

 be formed at the same temperature for concentrations lying between 

 n and d,. — On cooling the conversion L,^ —^ f^i -\- Suhcnoi takes 

 place on the line ndj)^, so that at last the liquid layer L^, which 

 is richer in phenol, has quite disappeared. vSo long as the three 

 phases are present the temperature remains constant, and this ex|)lains 

 the fact that Paterno and Ampola have found a somewhat oscillating 

 temperature of solidification of ± 1,74° in a certain range of concen- 

 tration. The temperature of the three-phase equilibrium Lj-j-Ty^+'S'^V/CT../ 

 was accurately determined by us by means of the resistance thermo- 

 meter, and found at J, 7°. 



As it was expected that the eutectic point lying under it, where 

 ice, solid phenol, and liquid coexist, would differ little in temperature 

 from the just mentioned three-phase equilibrium, this point too was 

 determined with the resistance thermometer, when the tenq)erature 

 of 1,2° was found. 



As was already observed before, the «nelting-point line of phenol 

 is only stable up to the point r/, for it appeared in oui- investigation 

 that in the stable state not the continuation <i d^, but the melting- 

 point line <! fd is found with a maxiinuin in /', which maximum 

 corresponds to the concentration (C„ H,, OH)^ . H^ ( ). In this case, 

 where mixed crystals play no j^art, this points to the fact that in 

 stable state a compound of the concentration mentioned above occurs, 

 which, as appeared to us, was easy to obtain l)y sudden cooling of 



