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CHAPTER VIII. 

 PICRIC ACID AND PICRATES. 



1. HISTORICAL. 



TRINITROPHENOL, otherwise termed picric acid, heated towards 

 300, decomposes with a sudden explosion, and its salts behave 

 in a similar manner. But the decomposition is complex, and 

 only takes place at a temperature higher than that of nitro- 

 glycerin, when oxidising bodies, such as potassium nitrate or 

 chlorate, are added. It occurs at a lower temperature than 

 with the pure acids and salts, and yields simpler products. 

 Powders of various natures are obtained in this way, some 

 having as base picric acid and sodium nitrate (Borlinetto 

 powders), others having as base potassium picrate associated 

 either with potassium nitrate (Designolle powders) or chlorate 

 (Fontaine powder); other powders again having as base 

 ammonium picrate with potassium nitrate (Brugere powder and 

 Abel powder). The chlorate powder has been proposed for 

 torpedoes only, it being very dangerous. On the other hand, 

 the powders formed with the nitrates can be employed in fire- 

 arms, especially ammonium picrate powder, which has of late 

 been greatly studied in France. We shall successively examine 

 the picric acid, potassium picrate, and ammonium picrate 

 powders. 



2. PICRIC ACID. 



1. Picric acid is a yellow body, in laminated and friable 

 crystals, having a bitter taste, very stable in itself, not easily 

 soluble in water, but soluble in all other solvents. 



When heated it melts, and can even be sublimed when 

 very small quantities are operated upon. But if the quantity 

 be at all considerable, or the acid be suddenly heated, it explodes 

 very violently. This property has occasioned serious accidents. 

 For instance, it has happened that experimenters have been 

 injured by throwing powdered picric acid into a furnace from a 



