Properties of Pure Substances : Nitrogen. 



29 



3. The compound decomposes with crepitation at a tem- 

 perature of about 200° C. (very rough). 



4. The compound is probably identical with the trimer- 

 curamine of Plantamour. 



5. It behaves as a dissociable compound on heating and 

 cooling, and can finally be entirely decomposed by repeating 

 the heating and cooling often enough. 



6*. An attempt to get the dissociation curve with such 

 accuracy as would allow the application of analysis failed, 

 through the want of a preliminary determination of the 

 relative capacity of tube and gauge. 



It now became necessary to repeat the experiment under 



Fig. 2. 



To gauge, 120 cm. of filamentary tube. 



_B f| A 



To pump.<=: 



Inlet for gas. 



y 



K- 



r 



i \l3C77l 



c 



29 cm 



\14 cm 





MERCURY LEVEL 



scrr 



Inside diameter of main tube 1*5 cm. ; thickness of walls °15 cm. 



slightly changed conditions, so that new facts might present 

 themselves and the previous results be controlled. I decided 

 to make a tube of such a kind that I could begin by sparking 

 it so that the sparks only passed through nitrogen, and then, 

 after a sufficient interval of time and at any convenient 

 opportunity, introduce mercury with a view to observing the 

 modified action. In order to vary the conditions, the whole 

 drying apparatus up to the sulphuric-acid tube was pumped 

 out afresh and filled with gas, which passed through the 

 reagents very slowly. This process occupied two days, one 

 day and a half it took to exhaust the vessels, and half a day 





