Intelligence and Miscellaneous Articles. 



383 



gating the tension of the vapour of solutions of such mixtures of salts 

 as Graham used. For Wiillner has found that the diminution of the 

 tension of the vapour for each salt and each mixture of two salts, 

 even when, from being salts of the same acid or the same base, they 

 do not act chemically upon each other, is a special function of the 

 temperature. Hence if, in the solution of a mixture, four salts are 

 formed, the diminutions of the tensions must be the same, whatever 

 be the compound in which the two acids and bases are brought into 

 solution. 



The author has undertaken the solution of these questions. He 

 worked with an apparatus used by Wiillner in his experiments. It 

 consists essentially of Magnus's modification of the shortened siphon- 

 barometer, in the closed limb of which is the liquid to be investigated, 

 while the open one is connected with a manometer and an air-pump, 

 by which the mercury in both limbs can- be kept at the same level. 

 From the position of the manometer, and the difference in the levels 

 of the mercury in the two legs of the barometer, the tension of the 

 vapour can be determined. The heating of the barometer was 

 effected in a transparent water-bath. 



The author used two solutions of salts mixed in equivalent quanti- 

 ties (the salts being dry) ; one of these solutions was as saturated as 

 possible (in the case of sulphate of potash not above 10 per cent.), 

 and the second half as saturated. The salts used were 



(1) KS0 4 + NaCl and NaS0 4 + KCl ; 



(2) KN0 6 + NaClandNaN0 6 + KCl; and 



(3) KS0 4 + NaN0 6 and NaS0 4 + KN0 6 . 



Of the numerous results obtained, the following Table furnishes 

 an example. Columns 3, 4, 5, and 6 give the diminution of tension 

 by the quantity of salt. Column 7 the corresponding diminution 

 when the solution was not obtained by dissolving dry mixtures of 

 salts, but was prepared by dissolving one salt in the solution of 

 another. 



1. 



Tempe- 

 rature. 



2. 



Tension 



of 

 aqueous 

 vapour. 



3. 



5KS0* 



+ 

 3-015 NaCl . 



4. 



4-175 NaS04 



+ 



3-84 KC1. 



5. 



lOKSO* 



+ 



6-031 NaCl. 



6. 



8-351 NaS04 



+ 



7-680 KC1. 



7. 



10KSO4 

 dissolved in 

 6-031 NaCl. 



8. 



Mean 

 for lper 



cent. 



salt. 



9. 



Calcu- 

 lated. 



12-86 

 15-24 

 16-47 



11036 

 12-900 

 13-952 



0-39 

 0-49 

 0-49 



0-35 

 0-50 

 0-50 



0-70 

 0-94 



0-89 



0-75 



0-85 

 0-90 



0-70 

 110 



0-92 



00722 

 0-0993 

 (0-0935 



0-0651 



00803 

 00816 



The author concludes from the values which he obtained, about 

 thirty in each case, between 12° and 96°, — 



1 . That the tension of the vapour of solutions which are prepared 

 with salts mixed in equivalent proportions is the same, provided the 

 constituents of the salts are the same. 



2. That the diminutions of tensions in the mixtures belonging to 

 each other, as also in the case of simple salts, increase proportionally 

 to the percentage amount calculated according to the first salt-mixture. 



