538 CONSIDERATION OF CARBON COMPOUNDS. 



power to unite with acids to form ethereal salts (esters), thus exhibit- 

 ing alcoholic character. When immersed in varying mixtures of con- 

 centrated nitric and sulphuric acids, and for different lengths of time, 

 di-, tri-, tetra-, penta-, and hexa-nitrate are formed, thus : 



C 12 H 20 10 + 2HNO, - 2H 2 + C u H 18 O 8 (NO,) a . 

 C 12 H 20 10 + 4HN0 8 - 4H 2 + C U H 16 O 6 (NO S ) 4 . 

 C 12 H 20 10 + 6HN0 3 = 6H 2 + C U H M O 4 (N0 8 ) 6 . 



The sulphuric acid used takes no part in the reaction, but facilitates 

 the same by absorbing the water which is eliminated. 



The di-, tri-, and tetrad-nitrate are soluble in a mixture of alcohol 

 and ether, which solution is known as collodion. These lower soluble 

 nitrates, better known as collodion cotton, are official in the U. S. 

 and British Pharmacopoeias as pyroxylin ; -colloxylin is also used as a 

 synonym in this country. In Europe, pyroxylin is applied to the 

 higher (penta- and hexa-) nitrates, which are insoluble in a mixture 

 of alcohol and ether, while colloxylin is applied to the soluble collo- 

 dion cotton. The penta- and hexa-nitrates form the highly explosive 

 gun-cotton. A solution of collodion cotton in molten camphor hard- 

 ens upon cooling and is then known as celluloid. When warmed it 

 becomes plastic and can be molded into various shapes. 



Flexible collodion is a mixture of collodion, castor oil, and Canada 

 balsam, which is much less constringent than official collodion. Can- 

 tharidal (blistering) collodion contains extract of cantharides and has 

 blistering properties. Styptic collodion contains tannin. For medi- 

 cation, any substance, soluble in ether, may be added to collodion, 

 such as iodine, iodoform, salicylic acid, croton oil, extract of Indian 

 cannabis, mercuric chloride, resorcin, pyrogallol, atropine, etc. 



Smokeless gunpowder is gun-cotton, first made gelatinous by 

 acetone, acetic ether, or like substances, then dried and granulated. 

 Smokeless powder occupies less space and burns more slowly than 

 gun-cotton. 



Experiment 65. Immerse 2 grammes of dry cotton for ten hours in a pre- 

 viously cooled mixture of 28 c.c. of nitric acid and 44 c.c. of sulphuric acid. 

 Wash the pyroxylin thus obtained with cold water until the washings have no 

 longer an acid reaction. Dissolve 1 gramme of the dry pyroxylin in a mixture 

 of 25 c.c. of ether and 8 c.c. of alcohol. The solution obtained is collodion. 



Pyroxylin in well-closed bottles exposed to light decomposes with 

 evolution of nitrous vapors and a carbonaceous mass is left. It 

 should be kept dry and in a carton. The compound ether nature of 

 all cellulose nitrates is shown by the fact that the nitric acid is elimi- 



