676 
ME. P. Q-EIESS ON A NEW SEEIES OF BODIES IN 
of the above-mentioned secondary product of decomposition, possesses an intense reddish- 
brown colour) is then evaporated on the water-bath. The residue is once more pressed 
and washed with a mixture of alcohol and ether to remove the reddish-brown substance, 
when the compound is obtained nearly white. By again pressing and dissolving the 
dry cake in a small quantity of absolute alcohol, filtering, and adding a sufficient amount 
of ether, the substance is obtained in white plates, which must be dried at once over 
sulphuric acid. 
0*735 grm. gave 0*3992 grm. of sulphate of potassium, corresponding to 35*00 per 
cent, of KIIO. 
Calculated. 
Found. 
g 6 h 4 n 2 
104 
64*92^ 
— 
KH0 
56*2 
35*08 
35*00 
160*2 
100*00 
The compound of hydrate of potassium with diazobenzol crystallizes in small, white, 
soft plates, which become reddish by exposure to the air ; they are very readily soluble 
in water and alcohol, but insoluble in ether. The solution has a strong alkaline 
reaction. A freshly prepared aqueous solution is but slightly coloured ; but by keeping 
for a short time it rapidly acquires a yellow colour, and ultimately a reddish-yellow 
substance is precipitated. Ebullition does not seem to accelerate this decomposition 
materially. The dry substance is very stable, and can be kept a long time unchanged. 
Heated alone it explodes at a little above- 130°; the explosion is accompanied by a 
slight report. 
Compound of Hydrate of Silver with JDiazobenzol, 0 6 H 4 N 2 , Ag HO*. 
This is obtained as a white or slightly chocolate-coloured precipitate, by treating a 
freshly prepared solution of the previous compound with a solution of nitrate of silver. 
After removing the mother-liquor, the precipitate is thoroughly washed with water, 
dried by pressing between filter-paper, and finally over sulphuric acid. 
0*5830 grm. gave 0*6772 grm. of CO and 0*126 grm. of water, corresponding to 31*68 
per cent, of carbon and 2*40 per cent, of hydrogen. 
0*9645 grm. gave 0*5955 grm. of chloride of silver, corresponding to 46*46 per cent, 
of silver. 
* It deserves notice that diazo-amidobenzol and the analogous double compounds likewise combine with bases. 
When speaking of these bodies (Ann. der Chem. und Pharm. Bd. cxxi, p. 362) I have pointed out that they all 
possess the property of forming insoluble precipitates with nitrate of silver. Without examining these pre- 
cipitates more closely, I then came to the conclusion that (judging from the manner in which they were ob- 
tained, and taking a few silver-determinations into consideration), they were simply combinations of the re- 
spective diazo-amido-compound with nitrate of silver. This view has proved erroneous ; for, on closer exami- 
nation, it was found that these bodies contain no nitric acid, but must be regarded as combinations of silver 
with diazo-amido-compounds, viz. G 12 H u N 3 , Ag. I intend subsequently to refer to this subject. 
