the Halogens, Nitrogen, Sulphur and Oxygen. 371 



Experiment 7. — Albumin from blood was charred in a 

 covered platinum crucible, and the residue was exposed to the 

 heat of a blast lamp five minutes after the escaping gases 

 ceased to burn. The charcoal, which was very bulky and soft, 

 contained 4'43 per cent of nitrogen. It gave off ammonia 

 when heated in steam. A portion of the charcoal after heat- 

 ing for three quarters of an hour to the melting point of cast 

 iron gave a distinct reaction for nitrogen by the test with 

 molten sodium carbonate, etc. 



Experiment 8. — -Carefully washed and dried egg albumin 

 charred as above yielded a charcoal containing 4 - 61 percent of 

 nitrogen. 



In experiments described hereafter the charcoal used was 

 not strongly heated and was made by charring sugar in a large 

 platinum dish heated by a Bunsen burner. 



Experiment 9. — 10 grams of sugar charcoal were heated in 

 a glass tube for a time to faint redness and then to the highest 

 heat of a combustion furnace. During the heating 7 liters 

 of pure nitric oxide* were passed over the charcoal. The 

 charcoal did not glow as when burning rapidly, and about one- 

 third of it was consumed. Carbonic oxide came off abundantly 

 and with it small quantities of carbon dioxide, ammonia, and 

 cyanogen. The charcoal after cooling was pulverized and 

 then heated to incipient redness in vacuo. Thus treated it 

 contained 3'44 per cent of nitrogen, but after heating for an 

 hour in a Perrot furnace it was free from nitrogen. The com- 

 plete removal of the nitrogen was doubtless due to the action 

 of vapor of water from the burning of the gas. 



Experiment 10. — This was conducted as nearly as possible 

 like the preceding experiment with the exception that pure 

 nitrous oxide was used. The product contained P09 per cent 

 of nitrogen. 



Experiment 11. — This was a duplicate of Exp. 10, with the 

 difference that the charcoal was allowed to cool in dry carbon 

 dioxide after the combustion in nitrous oxide was stopped. 

 3*85 per cent of nitrogen was found in the product. A part 

 of this nitrogenous charcoal was heated for an hour to the 

 highest temperature of a Perrot furnace. The charcoal was 

 held in the middle of a porcelain, tube by plugs of asbestos, 

 and lower end of the tube which was not heated contained 

 calcium chloride to dry the air in the tube. The charcoal 

 after exposure to the intense heat was found by the absolute 

 method to contain 0*46 per cent of nitrogen. The charcoal 

 was also further tested by heating with sodium carbonate, dis- 



* The nitric oxide used in this and subsequent experiments was made from 

 nitric acid by means of ferrous sulphate and was dried by sulphuric acid. 



