366 W. G. Mixter — Deportment of Charcoal with 



was found in first. The preparation h gave 14*3 per cent of 

 chlorine by the combustion method and 15 - 5 per cent by fus- 

 ing with soda and niter. The low result by the method of 

 combustion is due to the formation of carbon chlorides which 

 form a slight sublimate and sometimes oily drops on the am- 

 monia water. 375 grams of the chlorinated lampblack of h 

 were placed in a glass tube, the anterior end of which con- 

 tained lumps of caustic potash, and the air was exhausted by 

 a Sprengel pump. The part of the tube containing the lamp- 

 black was heated to redness for two hours while the exhaustion 

 was maintained by constant pumping. The evolution of gas 

 not absorbed by potash was slow and 22 cc were obtained. The 

 gas had a slight odor and burned with a blue flame. The 

 lampblack after heating in vacuo contained 8*5 per cent of 

 chlorine. 



Experiment 4- — Lampblack in compact pieces* was heated 

 in a current of chlorine for four hours in a porcelain tube to 

 the highest temperature of a gas combustion furnace. The 

 product after standing a day in the air contained 11"9 per cent 

 of chlorine. 10 grams of the chlorinated lampblack were 

 next placed in a porcelain tube which was connected with a 

 tube containing calcium chloride and slaked lime to absorb 

 water, chlorine and carbon dioxide. The air in the tube was 

 pumped out so completely that after nine hours no more air 

 was obtained by further pumping. The tube was then heated 

 to bright redness for three hours while the Sprengel pump was 

 in constant action. 30 cc of a gas were obtained which had a 

 slight odor and burned with a blue flame. The chlorinated 

 lampblack after ignition in vacuo contained 9 - 04 per cent of 

 chlorine. 



Experiment 7. — The lampblack of the preceding experiment 

 with 9'04 per cent of chlorine was placed in a porcelain tube 

 plugged with asbestos, and the sugar charcoal of experiment 2 

 containing 4*6 per cent of chlorine was put into a covered 

 porcelain crucible. Both were heated in a covered clay cru- 

 cible in a coal fire for fifteen hours, much of the time to a white 

 heat. The porcelain was softened. No chlorine was detected 

 in either carbon after the ignition. The test was made by cau- 

 tiously heating the carbon with soda to which niter was 

 gradually added and then testing for chlorine by the usual 

 method. The ash of the sugar charcoal increased from 0'04 to 

 0*17 per cent, due undoubtedly to the absorption of vapors, 



*The lampblack was obtained in compact form by subjecting it to a pressure 

 of about 2500 pounds to the square inch in a hydraulic press. Pressed lamp- 

 black is oue of the best forms of charcoal for many kinds of experiments as it is 

 uniformly porous and consists of very minute particles. That used in the experi- 

 ments sank slowly in water, that is, its apparent density was 1 while the true 

 density was according to Mallet 1*7. 



