( 1168 ) 
94.721 0 0 0 5.279 NaCl 
g. 88.387 0 8.708 0 2.905  NaCl+CuCl,.2H;0 
L 3814 0489 0 0.639 5,065  Na;SO,+NaCl+D 
9249 0 4218 0.758 4.605 NaCl+D 
g 98023 0550 1000 0 1.821 es 
™ 99.089 0,445 3177 0 1.239 atte 
= 91495 0389 4,506 0 2.910 as. 
89,023 0.311 7.559 0 3,107 EE 
m. 88132 0.299 8486 0 2.083 __ CuCl).2H,O-+NaCl+D 
When studying the given compositions of the solutions we must 
remember that these may be expressed in different ways. 
Let us take a solution which contains: 
a Mol CuSO,, 6 Mol CuCl,, c Mol Na,SO, 
and, therefore, 100—a—b—c Mol H,O. 
In consequence of the relation ; 
Na,SO, + CuCl, = CuSO, + Na,Cl, 
we may also express the composition as: 
a Jz Mol CusO,, b —a Mol CuCl,, c — x Mol Na,S0,, 
z Mol Na,Cl, and 100—a—b—c Mol H,O. 
We notice that, in this manner, the composition of a phase may 
be expressed in an infinite number of ways. 
If b<c and «=—4, the composition becomes: 
a+b Mol CusO,, c— b Mol Na,SO,, b Mol Na,Cl, 
and 100—a—b—c Mol H,O. 
3. THE ISOTHERMS BETWEEN 35° AND 25°. 
On lowering the temperature the surfaces and saturation lines of 
fig. 1 undergo a slight change of form but the isotherm up to about 
32.5° retains the shape of fig. 1. 
For at 32.5° a new phase appears, the hydrate Na,SO,.10 H,0. 
At this temperature there appears in point a of fig. 1 a new 
saturation surface which extends on further lowering of the tempera- 
ture. At 82° it passes through the point 4 and below this tempera- 
ture the isotherm assumes a form as indicated in fig. 2. This has 
been determined at 25°. 
