409 



Tliiis according to calculation the mixture C^C/^ — C^H^ {p}^ = 4:5,0 

 and 47,9) would have to give a heat of mixing = -\- 2,0 gr. cal., 

 whereas -j- 2J ,4 was found by Young. The valne of ^"/y, viz. — 0,00130, 

 found by Young, points to a pretty great volume contraction which, 

 however, does not account for the too great positive value foi- w. 

 Also the vapour-tension line deviates here. 



The mixture C^H^ — CCl^ (/9&^=41,6 and 45,0) leads us to expect 

 -j- 3,9 for IV, whereas w is = — 8,5 according to Young. To this 

 belongs '^'"/y = — 0,00070 according to the same author, and accord- 

 ingly 10 and Av are both negative. 



3. C^HiAc — CCl^. The calculation of this mixture may be repio- 

 duced here. We have : 



giving : 



w =z 7^ , . 1,054 X 556,2 (0,006577 -f 



+ '/, 0,9704. 0,0811 {0,0231— V, 1,054.0,0811 . 1,9543 |) 



= 2052 (0,006577 + 0,01312 | 0,0231 -0,0418j) 



= 2052(0,006577— 0,000245)=: 2052 - 0,006332 =+ 13,0 gr. cal. 



Young found — 20,1. Calculation here gives a negative value for 

 Ay, the correction term not being even so much as 47o of the 

 principal term. For ^7" ^^ calculate: 



^7„ = 7,, X 1,054 X 0,081 1 X ( - 0,187) = - 0,00067. 



The value + 0,00030 was found by Young. Again iv and Ay 

 (found) have opposed signs, which is strange, and renders the accuracy 

 of Young's values somewhat questionable. (Cf. also the last Footnote). 



Let us now give a few examples of recognized associated com- 

 ponents. 



4. C\H,— C\H,OH. We have in this case: 



from which follows: 



