and Attached Water, 



59 



which gave -2510 of BaS0 4 , 



showing '0857 or 20*3 per cent, of S0 3 in residue. 

 The mother-liquor of B showed in 

 2-434 grms. 



•4320 grm. of residue, 

 which gave -2390 „ of BaS0 4 , 



showing *082 or 18*8 per cent, of S0 3 in residue. 



§ 120. Sulphate of Potassium and Choride of Sodium as a 

 Cryohydrate. — The behaviour of the mixture of these salts also 

 points to the non-existence of either. 



S-Q grms. of K 2 S0 4 , 



5-85 „ NaCl 



( = K 2 S0 4 + 2NaCl) 

 were dissolved, mixed, concentrated to saturation, and cooled. 

 At first granular crystals fell out. A cryohydrate began to 

 form at —6°. The whole was dry at — 12°*5, whereas if 

 Nad had been present it would have required —22°. A 

 mixture in the ratio K 2 S0 4 + NaCl behaved in a similar way, 

 but was dry at -10° C. 



§ 121. Sulphate of Potassium and Chloride of Ammonium 

 as a Cryohydrate. — Similarly to § 120, a mixture in equivalent 

 proportions ofK 2 S0 4 andNH 4 Cl became quite dry at —12°. 

 The salt NH 4 C1 alone requires —15°. 



§ 122. In the subjoined Table the results in regard to mix- 

 tures of salts as cryohydrates and cryogens are compared with 

 the behaviour of their constituents in each capacity. 



Table XY. Cryohydrates and Cryogens of equivalent 

 mixtures of two salts. 







Temperature of soli- 



Temperature 









dification of each 



of final solidi- 



Temperature 



Mixed salts. 



constituent as 



fication of 



as cryogen of 







cryohydrate. 



mixture as 



mixture. 









cryohydrate. 





(a) 



(*) 



(«) W 



(a+b) 



{a+b) 



(1) KN0 3 



+Na]S T 3 ... 



- 26 —17-5 



-17 



-168 



(2) KC1 



+NaCl 



-11-4 -22 



-21 



-21-8 



(3) KC1 



4-NH 4 Cl... 



-11-4 -150 



-17 



-18 



(4) Ba2N0 3 



+ Sr2N0 3 .. 



- 0-8 - 60 



- 4-3 



- 5-8 



(5) BaCl, 



+SrCL 



- 80 -170 



-18 



-16-7 



(6) (NHJ 2 SO. i +Na 2 S0 4 ... 



-170 - 7 



- 7 



-16 



(7) 2KNO s 



+Na 2 S0 4 ... 



- 2-6 - 7 



- 5 





(8) 2NaN0 3 



+K 2 S0 4 ... 



-17-5 -11-2 



- 5 





(9) K 2 S0 4 



+2NaCl ... 



- 1-2 -220 



-12 5 





This Table furnishes examples of the three typical kinds of 

 relationship between the constituent salts and the mixture of 

 them : namelv, 



