670 
ME. P. GEIESS ON A NEW SEEIES OE BODIES IN 
cury or iodide of nitrogen. About a gramme of this substance causes by its explosion 
a concussion like that produced by firing a pistol. 
The destructive action of such an explosion is likewise extreme. Iron slabs of several 
lines in thickness were found smashed to atoms when a somewhat larger quantity was 
exploded upon them. Friction, pressure, and concussion also cause it to explode. The 
smallest particles of this substance, accidentally dropped upon the floor of a room, when 
trodden upon when dry, gave rise to a series of explosions attended with flashes of light. 
The properties of the nitrate of diazobenzol render it absolutely necessary that the 
greatest precaution should be observed when manipulating it. The portion of the sub- 
stance required for analysis having been well washed with ether*, was placed in a pla- 
tinum crucible and dried over sulphuric acid. Concussion or pressure had to be care- 
fully avoided, especially with the dry substance, on account of its great explosiveness. 
For the above-mentioned reasons I abstained from analyzing this compound in the 
usual manner, especially as I had opportunities of ascertaining the composition of 
analogous but less dangerous compounds by the ordinary analytical method. I have, 
however, been enabled to arrive at a knowledge of the composition of nitrate of diazo- 
benzol by the very interesting change which an aqueous solution undergoes by the action 
of heat. By ebullition the compound is transformed under the influence of the water 
into carbolic acid, nitrogen, and nitric acid ; and by estimating the quantities of the two 
latter products I have arrived at the true composition of the explosive substance. 
9 6 H 4 N 2 , NH9 3 +H 2 0=€ 6 H 6 0+NH0 3 +N 2 . 
Nitrate of diazobenzol. Carbolic acid. 
The method employed for the determination of the quantity of nitrogen evolved by 
the ebullition of the aqueous solution of the explosive compound is as follows : — The 
solution was introduced into a flask and a stream of carbonic acid gas passed through it. 
When the air was expelled, the delivery-tube was placed under a graduated cylinder 
containing solution of potassa, and the contents of the flask heated to ebullitionf . 
* When it is intended to recover the ether employed in the preparation of nitrate of diazobenzol, it is 
advisable, in order to avoid explosions, to shake the ethereal mother-liquor first with a little water, so as to 
dissolve any traces of the diazo-compound suspended in it. I have had a most dangerous explosion by neglecting 
this simple precaution. A large quantity of ether, which had been employed for the precipitation of the new 
compound from its alcoholic solution, had accumulated. From this liquid a few crystals had been observed 
to have separated. Their number seemed, however, to be so small, that it was deemed unnecessary to remove 
them from the vessel containing the ethereal liquid for distillation. As soon as the vessel became warm in the 
water-bath, and before the boiling-point of the ether had been reached, a fearful explosion took place, shattering 
the whole of the distilling apparatus to pieces and setting fire to the ether, the flame of which spread most 
alarmingly through the laboratory. The gas-flames, which were burning at the time in the room, were suddenly 
extinguished by the violent pressure upon the atmosphere, and all those working in the laboratory (who 
fortunately escaped unhurt) were for a moment deprived of their breath. The explosive properties of the 
nitrate of diazobenzol may perhaps at a future period find practical application. 
t In all analyses mentioned herein the analyzed substances are understood to be desiccated by Sulphuric acid 
previously, unless the contrary is distinctly stated. 
