Ral A hee 
440 
The existence of such a suboxide would not prevent the determination 
of the equilibrium pressure in the system, Ag, Ag,O, O, for this pressure 
could readily be calculated from the equilibrium pressure in the system 
Ag,O, Ag,O, O,, and that in the system Ag,O, Ag, O,. However, I 
shall show that in experiments covering a wide range of temperature, the 
suboxide never appeared and that the experiments which led M. Guntz 
to believe in its existence are probably to be interpreted otherwise. 
I shall first describe measurements of the decomposition pressures at 
several temperatures and then show that the quantities thus obtained 
represent true equilibrium in the system Ag,O, Ag, O.. 
Two samples of silver oxide were used. These will be referred to 
as A and B. A was prepared from hot, dilute barium hydroxide and 
silver nitrate as described in my paper on the kinetics of the silver oxide 
decomposition, carbon dioxide being excluded.* B was the preparation 
of Merck, labeled “highest purity.” Both samples before being used 
were heated for several hours at 300°. 
DECOMPOSITION PRESSURE AT 325°. 
The first experiment was made at 325° * in the thermostat of molten 
sodium and potassium nitrates which I have described in the paper just 
mentioned. The apparatus for measuring the pressure consisted of a 
stout, brass tube, about 2 meters long and 1 centimeter in internal di- 
ameter, closed at the lower end and at the upper connected with a metallic 
manometer. In the lower end of the brass tube was fitted a thin, glass 
tube 7 cm. high containing the silver oxide (Sample B). In order as far 
as possible to diminish the total air space in the apparatus, the rest of the 
brass tube was filled as nearly as possible with a close fitting glass rod. 
After the apparatus had been exhausted through a stopcock provided for 
this purpose the lower end of the tube was introduced into the thermostat 
to a depth of about 30 cm. 
The decomposition began in a few hours and in five days the pressure 
reached a constant maximum as shown in Table I. 
TABLE I. 
Time in hours. - Pressure in atmospheres. 
12 18.5 
24 26.5 
48 29.8 
72 30.1 
96 31.5 
120 31.8 
144 31.8 
® Zeit. Phys. Chem. (1905), 52, 310; Bulletin of the Bureau of Government 
Laboratories, Manila, No. 30. 
*All thermometers used were compared with Reichsanstalt standards. The 
corrected temperatures are given. 
