1114 
gaseous NH, first the As,O, is dissolved and an unsaturated 
solution occurs and that on further addition of NH,, the solid 
NH, AsO, is separated; the solution follows the curve bed in this case, 
starting from 6 and gets, therefore, gradually poorer in As,O,, which 
is deposited as NH,AsO,. We imagine also in fig. 1 the line NH, — 
Ds, to be drawn; its point of intersection with W—As,O, is 
represented by /. The point 4 indicates a complex which contains 
+91.5°/, As,O, and consequently + 8,5 °/, water. Now we take 
a complex g between h and f; this contains, therefore, more than 
22,5°/, and less than 91,5°/, As,O, and it consists of solution 
a + solid As,O,. When we bring NH,-gas into this complex, it follows 
the line g—-NH,; this line intersects, starting from g, first the 
region ab As,O,, after that the threephasetriangle 6. Do1,. As,O, 
and afterwards the region bcd. As,O,. Hence it follows that on 
addition of gaseous NH, first As,O, is dissolved until solution b 
T-ABE BE: L 
Compositions in percentages by weight at 309, 
of the solution | of the rest | 
| | ‚solid phase 
Oo NH3 Io As203/ fo NH3_%o As203, 
—————— en 
o | 2.26 | — EAF ND 
1.41 | 10.98 | 0.37 | 59.79 | „ 
2.78 | 20.49 | 1.24 | 63.10 ; 
2.86 | 21.17 | 1,21 | 64.26 | : 
5 ie at cag de Nn 
3.13 | 12.30 | 7.25 | 38.59 3 
3.18 | 11.13 | 7.51 | 38.39 . 
3.91 1265 | 8.24 | 35.80 | . 
5.82 5.61 | 9.08 | 36.44 ile, Gas 
6.08 Hp eaten ie, 
9.25 | 3.44 | 11.42 | 41.79 P 
9.93 | 3.20 | 11.74 | 42.44 ; 
10.06 | 3.14 | 12.22 | 49.14 é 
13198.’ aan olsa eten 
14.28 | 2.16 13.77 | 44.78 eae 
