1112 
The point Dei, represents the NH,AsO,; in order tô find the 
position of this point in the triangle, we must consider that: 
2 NH, AsO; ==(NE.) EO Ag SD 
the salt NH,AsO, contains consequently 13,6°/, NH,; 7,2°/, H,O 
and 79.2°/, As,O, so that the position of the point Do, is known. 
The point Dos; represents the NH,H,AsO,; as 
2 NH, AsO, =] (NH) 0), ASD Se 
this salt contains,.11.9.°/, NHS 43:0°/, BO and 69.24/ As 0 
When we draw in the figure the points Do;,; and Ds3,, then it 
is apparent that they are situated on a straight line with the angle- 
point IV. That this must really be the case, follows also from the 
equation 
NH,AsO, + H,O = NH,H, AsO, 
from which it is apparent that the NH,H,AsO, may be considered 
as consisting of NH,AsO, and H,O. 
Curve ab represents the solutions saturated with solid As,O,; 
these complexes have been shaken during about a month at 30°. 
The As,O, which we have used was an extremely fine flour-like 
powder; in each of the small bottles we brought a little sublimated 
As,O, and a little As,O, which was recrystallized from a strong, 
heat solution of chlorie acid. 
Point @ represents the solubility of As,O, in pure water; as it is 
apparent from table 1 we find for this 2.26°/,; Bruner and TorLoczkKo 
found that at 25° and 39,8° in 100 Gr. water 2.03 and 2.93 Gr. 
As,O, are dissolved. It appears from the analysis of the rests that 
the solid phase is not a hydrate, but that it is the anhydric 
As,Q,. 
Fig. 1. 
Curve bed represents the solutions with Dei, —= NH,AsO,. As the 
