214 NITROGEi:^ BODIES OF MODERN CHEMISIHY. 



nitric acid develops heat and gases, and wlieu the masses have for a 

 time acted ou each other, they are poured into an abundance of cold 

 water. Then, while the benzol, being lighter than water, floats on the 

 surface, the mirbanol, wliich is heavier, sinks underneath ; thus the ni- 

 trobenzol is prepared from the mixture of benzol with red fuming nitric 

 acid. This crude mirbanol, which has still an unpleasant odor, is 

 Avashed with weak carbonate of nitrogen, and then distilled off with ex- 

 treme care. It is unsafe, after washing it, to place this compound in a 

 retort over a fire, for, in case it approached the boiling temperature, 

 there would be a flash, a fearful explosion, and the retort would be shat- 

 tered. It must not be forgotten that, although this compound is not 

 used for explosive purposes, it is a nitrogen body; you have admitted a 

 wolf into the sheepfold; j^ou have introduced the element of inflamma- 

 bility — oxygen — among the atoms of hydrogen, and when once the 

 kindling takes place the hydrogen burns throughout the whole mass. 

 And yet the crude mirbanol is distilled, because the consumption of it 

 depends entirely on its freedom from color. This is accomplished by a 

 chemical process, whereby the crude mirbanol is placed in a retort and 

 the vapor of water introduced. At first, the water is condensed in the 

 retort, but the vapor being constantly renewed, the water at length at- 

 tains the boiling-point, is again vaporized, and escapes into the receiver 

 at a temperature, however, below the boiling-point of mirbanol, and the 

 latter is carried along by the watery vapor into the receiver. Of this 

 device much use has been made, because this method of distillation at a 

 low temperature greatly improves the odor and discharges the color of 

 the substance distilled. I beg you not to suppose that the artificial 

 mirbanol thus obtained from the crude uitrobenzol can be a substitute 

 for the genuine oil of bitter almonds — a costly, natural ethereal oil. If 

 you compare the two, j6u will find it absurd to give the same name to 

 the former, so delicate and fresh is the genuine' hydro-benzole, rela- 

 tively to the crude and harsh uitrobenzol. They are indistinguishiible, 

 however, in a diluted state, and in alkaline fluids, particularly in lye 

 compounds; in soaps the artificial oil is altogether preferable. Of 

 these common products, for overcoming strong odors, the genume, 

 tine bitter-almond oil would be wasted— it would be lost — overpowered 

 entirely by the rancid odor of the soap, for example, and would be less 

 efi'ective than its more powerful companion. 



But this is not its only use. When mirbanol is exposed to hydrogen 

 in a nascent state, a nitrogenous compound is formed, aniline, which is 

 merelv phenylamin : 



This is a substance whose synonyms bevrilder the beginner in our 

 science. Amidophenas, benzidam, krystallhie, kyanol, aniline, phenyla- 

 min, they are all the same, but, singularly enough, their production was 

 accompanied by wonderful misapprehensions. A chemist separating it 

 from coal-tar, supposing.it an oil, and observing that it gave a blue color 



