36-i W. G. Mixter — Deportment of Charcoal with 



Carbon 96-17 95-13 



Hydrogen 0*84 0-75 



Ash 1-56 1-08 



Oxygen by difference 1*43 2-44 



These results are interesting as they show how tenaciously 

 charcoal retains hydrogen even after ignition in chlorine. 



While attempting to prepare for use in an investigation 

 amorphous carbon free from hydrogen the writer observed 

 that charcoal retains considerable chlorine at high tempera- 

 tures. This fact has doubtless been observed but there appears 

 to be nothing on the subject in the literature of chemistry 

 except the statement by Schonbein* that charcoal absorbs 

 chlorine and retains some of it when heated. 



Experiments were made with amorphous carbon from vari- 

 ous sources, but only the results will be given that were ob- 

 tained with three varieties, viz : sugar charcoal, lampblack, 

 which is finely divided charcoal, and gas carbon. The rirst 

 was prepared by charring in an open platinum dish cane sugar 

 which was almost free from ash. The charcoal was pulverized 

 in an agate mortar, moistened with sugar syrup and then 

 pressed in a hydraulic press. The pieces were next heated to 

 redness and plunged into a thick syrup, and this treatment was 

 repeated until the charcoal would sink in water without boil- 

 ing to expel the air from the still porous coal. Finally, the 

 sugar charcoal was heated intensely for several hours in a cruci- 

 ble by a charcoal fire in a wind furnace having a strong 

 draught. The method employed for estimating hydrogen was 

 as follows : the charcoal was heated to redness in a platinum 

 tray, allowed to cool in a desiccator, then weighed and placed 

 in the combustion tube and then, in order to drive off ab- 

 sorbed water, it was heated to faint redness for half an hour 

 in a current of dry air in which it did not ignite. The com- 

 bustion was made in oxygen dried by oil of vitriol, solid 

 caustic potash, and finally, calcium chloride. An ordinary 

 calcium chloride tube was used to absorb the water of the 

 combustion. In a blank test of the apparatus the calcium 

 chloride tube gained 0'2 milligram. One lot of sugar char- 

 coal prepared as described yielded 0*13 per cent of hydrogen, 

 1-12 gram being used for the combustion. 1*25 gram of an- 

 other preparation gave 0126 per cent of hydrogen and O04 

 per cent of ash. The sugar charcoal burned with difficulty in 

 oxygen, was hard enough to scratch glass, and was a good con- 

 ductor of electricity. 



The lampblack used was of a kind made from natural gas 

 known as "Diamond Black.'' It is well described by Mallet. f 



. Ann., lxxiii, 326. f Ohem. News, xxxviii, 94. 



