DOUBLE SALTS 147 
TABLE IV 
SoLuBILITY CURVES FOR DouBLE SALTS AND THE CONSTITUENT 
SIMPLE SALTS 
These temperature-concentration curves represent on hori- 
zontal axes at both sides of the vertical temperature axis the 
composition of solutions saturated with two sulphates and in 
equilibrium with two solid phases. 
CURVE: SOLID PHASES: 
A mixture of the two 
Simple Salts 
FG and FG’ 
Na,SO,. 10H,O + 
M “SO, . 7H,O 
A mixture of the Double 
Salt and Glauber’s Salt 
GK and G’K’ 
Sedium- Magnesium Sulphate 
(Asfrakanile) 
Naso, toH ie Ses 7HO $s, Na torso), 4H O+13H,0 
—— Transition Inte a4 12-25° 
Na,M”"(SO,),. 4H,O + 
Na,SO,. 10H,O 
A mixture of the Dowdle 
ey Salt and the Vitriol 
GHandG’H Na,M’’(SO,)o- 4H,O + 
M’SO,.7H,O 
MJ and M’J’ Zhe pure Double Salt. 
GG’ is the Transition Point. 
MM’ is the end point of the Transition 
Interval. 
mals. H¢S0, t mols, Na So, 
4 i rea 
tn 100 mols 19 Temperature in 100 mols. ¢ 
Sodium- Zine Sulphate Sodium- Nickel Sulphate 
Na So. 1oH {0+ ZnSO, 2-7, goat eS Na S010H,0+NiSO- lds = NaNi(SO),- -gHO+I3HO 
Transi fon eee: 8-7 Gd Transition Inferval= 0 
a Bi bs TY 7 CELA Le 
ow alia AMAT EZ 
WecHEnAN2as oul Genoa ze 
555 sw i nO A 
emgiaid lela eli da Ak 
mols. ZnSO. mols. NaS0, mols. Na,SO. 
i 
mals _Niso, 
—,* 
‘1@0 mols. Ho Temperature in 100 mols. H,0 
tn 100 mols. Ho Temperature in 100 mols H,0 
the case of the double acetate of copper and calcium (p. 137), or 
by a change in state of aggregation, as in the case of astrakanite 
(p. 142). 
