Experimental and Applied 247 



and water are placed upon a filter paper, which is then transferred 

 to a bottle provided with an indiarubber cork. Through the cork, 

 glass tubes are passed, and so arranged that a stream of coal gas 

 may be led into the vessel to completely expel the air. After ex- 

 pelling the air, a little strong ammonia solution is introduced by 

 means of a separating funnel previously inserted through the cork. 

 No change in the substance of the paper is observed. The stream 

 of coal gas is now stopped, and atmospheric air is introduced. 

 Reaction rapidly ensues, with development of the blue colour of 

 the ammoniacal cupric compound, accompanied by solution of the 

 cellulose. The details of the arrangement of the experiment are 

 immaterial, and may be varied in a number of ways. 



On the theory of the action of cellulose solvents, read a paper 

 by the authors in Bull. Soc. Chim. 1893, 295. 



Cellulose Xanthate. In preparing the solution of the cellulose 

 thiocarbonate for use in the laboratory it is better to employ a ' rag ' 

 cellulose (cotton and linen) disintegrated by the process of * beat- 

 ing ' in a paper mill, which can be easily procured. If obtained 

 in the moist condition the cellulose may be air-dried previously 

 to treating with the 15 p.ct. solution of NaOH. The cellulose and 

 the alkaline lye may be thoroughly incorporated by grinding 

 together in a mortar in the calculated quantities to finish the 

 alkali cellulose so as to contain 



Cellulose, 100 ; caustic soda (NaOH), 45 ; and water, 250-300 ; 



or the cellulose may be treated with the 15 p.ct. NaOH solution 

 in excess, and, after standing some time, the cellulose may be 

 drained off on a filter of perforated zinc and squeezed to retain 

 three times its weight of the solution. 



As the process of 'mercerisation ' requires some time for com- 

 pletion, it will be found advantageous to set aside the moist alkali 

 cellulose in a closed bottle for two or three days before sub- 

 jecting it to the solvent reaction. This reaction proceeds spon- 

 taneously at the ordinary temperature ; the alkali-cellulose and 

 carbon disulphide (40-100 parts cellulose) are brought together 

 in a stoppered bottle, vigorously shaken together for a minute 

 or two, and set aside for two or three hours. The resulting 

 yellowish mass is covered with water and allowed to stand some 

 hours, then vigorously stirred with addition of water, in quantity 



