THE ODOUR OF BITTER ALMOND. 183 
almonds, at the same time reminding one of oil of cimnamon, and 
possesses a sweet and burning taste. It boils at 210°, and at a 
low temperature solidifies in large needles, melting at 3°. In 
water it is scarcely soluble, but it dissolves readily in alcohol, 
ether, benzene, and concentrated nitric acid, and is itself an 
excellent solvent for many organic substances which are sparingly 
or not at all soluble in the ordinary solvents. 
Nitrobenzene is poisonous, especially when the vapour is 
inhaled. 
It is manufactured on a large scale by allowing a well-cooled 
mixture of fuming nitric acid, free from chlorine, and concentrated 
sulphuric acid to flow into benzene, contained in cast-iron vessels 
provided with agitators. The mixture must be kept very cool. 
Towards the end of the reaction, however, the temperature may rise 
to from 80° to 90°. When the reaction is over the product is run 
into tanks; the acid mixture separates as a layer at the bottom, 
whilst nitrobenzene, being insoluble in the’acid, goes to the top. 
The uncombined acid layer is drawn off and the nitric acid recovered. 
Crude nitrobenzene contains more or less benzene which has 
escaped the reaction. To remove the latter, the crude product is 
treated with steam, while the benzene distils over with a small 
quantity of nitrobenzene. The residual nitrobenzene is washed 
with caustic soda and water, and if necessary purified by distil- 
lation in high pressure steam. 
Messrs. Schimmel & Co. report that “the competition of the 
cheap English nitro-toluol, the Pseudo-Mirbane of commerce, has 
made the laborious and dangerous manufacture of this poisonous 
body (nitrobenzene) quite unremunerative. The mania for 
cheapness has brought about a condition which deserves to be 
more closely considered. It should be premised that the odour of 
bitter almond is peculiar to nitrobenzene, so that those persons 
who buy an impure preparation mixed with nitrobenzene deceive 
themselves if they expect to obtain with it the same effect as with 
the pure compound. Of this they may convince themselves by 
making a comparative examination of the strength of the two 
qualities.” This Report, dated April 1891, further states that 
the opinion of an expert employed to estimate a commercial 
sample of this kind in connexion with the prosecution of the 
consigner, was given as follows :—“‘The so-called Mirbane oil 
contains no noteworthy proportion of nitrobenzene, of which it 
