83% ON THE CARBONACEOUS PRINCIPLE. 



cd with potas- of charcoal, for five minutes ; and to estimate the effects of 

 fiium. fjjg me tallic oxides and potash in the green glass tube, I 



made a comparative experiment, as in the case of plumbago ; 

 but there was no proof of any oxigen being furnished to 

 the potassium from the charcoal in the process, for the 

 compound acted upon water with great energy, and produced 

 a quantity of inflammable gas, only inferior by one twelfth 

 to that produced by the potassium, which had not been 

 combined with charcoal, and which gave the same diminu- 

 tion by detonation with oxigen; and the slight difference 

 may be well ascribed to the influence of foreign matters iu 

 the charcoal . There was no ignition in the process, and 

 no gas was evolved. 4 



Compound pro- The compound produced in other experiments of this 

 kind was examined. It is a conductor of electricity, is of 

 a dense black, inflames spontaneously, and burns with a 

 deep red light in the atmosphere*. 

 Diamond could The nonconducting uature of the diamond, anditsinfwsi- 

 not be acted on bility, rendered it impossible to act upon it by voltaic 

 electricity ; and the only new agents which seemed to offer 

 any means of decomposing it, were the metals of the 

 alkalis. 

 Heated with When a diamond is heated in a green glass tube with po- 



potassium, tassium, there is no elastic fluid given out, and no intensity 

 of action ; but the diamond soon blackens, and scales 

 seem to detach themselves from it, aud these scales, when 

 examined in the magnifier, are gray externally, and of the 

 colour of plumbago internally, as if they consisted of 

 plumbago covered by the gray oxide of potassium. 

 i:iWdrogen gas. In heating together three grains of diamonds in powder, 

 and two grains of potassium, for an hour, in a small retort 

 of pltte glass filled with hidrogen, and making the compa- 

 rative trial with two grains of potassium heated in a similar 

 apparatus, without any diamonds, I found, that the pot- 

 assium which had been heated with the diamonds produced, 

 by its action upon water, one cubical inch and T 3 5 of in- 



* In the Bakerian Lecture for 1807, I have mentioned the de- 

 composition of carbonic acid by potassium, which takes place with 

 inflammation. If the potassium is in excess in this experiment, the 

 same pvrophorus as that described above is formed. 



flammable 



