Dr. J. Stenhouse on Chloropicrine. 55 



resin isthe produce of the Xanthorcea hastilis. It can be pur- 

 chased in London for a shilling the pound. It yields half its 

 weight of nitropicric acid : eight ounces gave four ounces of 

 acid, which was much more easily purified than that prepared 

 from indigo; it contained, however, some oxalic and a very 

 little nitrobenzoic acid. This yellow gum-resin, as I showed 

 in a paper published in this Journal nearly three years ago, 

 is therefore by far the most ceconomical source of nitropicric 

 acid. 



The resinous portion of gum-benzoin, after all the benzoic 

 acid it contains has been extracted by boiling it with alkalies, 

 when digested with nitric acid also yields a great deal of char- 

 bazotic acid. This, in fact, is the most advantageous way in 

 which this otherwise useless product can be employed. I have 

 found that the resinous portion of balsam of Peru is also con- 

 verted into charbazotic acid when boiled with nitric acid ; but 

 I could not procure charbazotic acid from balsam of Tolu. 



When the chrysammic acid of M. Schunck is boiled with 

 hypochlorite of lime, it yields abundance of chloropicrine ; 

 and, as might almost have been expected, the same is the case 

 with the styphnic acid of Messrs. Will and Boettger, or the 

 oxypicric acid of Erdmann. With chlorate of potassa and 

 muriatic acid these acids are also transformed into chloranile 

 and chloropicrine. 



Chloropicrine prepared from any of these sources has the 

 following properties. It forms a transparent colourless oil 

 which refracts the light pretty strongly. Its specific gravity 

 is 1 •6657. Its smell when diluted is aromatic and very peculiar; 

 when undiluted, it affects the nose and eyes as strongly as 

 chloride of cyanogen or oil of mustard, only its effects are not 

 so permanent. Chloropicrine is perfectly neutral to test-paper. 

 It is nearly insoluble in water, but dissolves very readily in 

 alcohol and in aether. It is not acted on by sulphuric, muriatic, 

 or nitric acids in the cold ; and when boiled along with these 

 acids it distils over unchanged. When a small bit of potassium 

 is dropt into a quantity of the oil and a gentle heat is applied, 

 the chloropicrine is decomposed by a most violent explosion. 

 If the potassium is put into the oil at the ordinary temperature 

 no explosion takes place, and in the course of a day or two it 

 is converted into a mixture of chloride of potassium and nitre. 



These salts, when tested by sulphuric acid, gave no trace of 

 nitrous gas. Aqueous solutions of the alkalies may be kept 

 in contact with chloropicrine for a considerable time without 

 producing any perceptible effect upon it ; but when an alco- 

 holic solution of potassa or soda is employed, the chloropicrine 

 is slowly decomposed, and crystals of chloride of potassium 



