NITRIC OXIDE, AND CHLORO-HYDRIC ACID. 61 



reaction to nitrous acid, imagined to have been derived from the nitrous oxide. 

 But the follov^ing experiment settled this point. A portion of the salt was 

 introduced into a small tubulated retort. Cold water, recently boiled to free it 

 from atmospheric air, was added to it, until all the nitric oxide was disengaged. 

 A concentrated solution of fused chloride of potassium was next added, and the 

 whole distilled nearly to dryness. The product of this distillation was a colour- 

 less liquid, first slightly acidulated, but becoming afterwards strongly acid. It 

 precipitated nitrate of silver very copiously, and left, when evaporated, no resi- 

 duum. At no period of the process could any free chlorine be noticed. 



8. Heated in an atmosphere of dry hydrogen, the salt first gives off water, 

 and afterwards a white sublimate of chloride of ammonium, in accordance with 

 the fact that hydrogen and nitric oxide gas, in contact with heated spongy pla- 

 tinum, form ammonia, which, in this case, combines with the hydro-chloric 

 acid, and forms chloride of ammonium. The reduced platinum is black, much 

 resembling, in appearance, the preparation of Liehig. It ignites hydrogen, and 

 assumes a metallic appearance when rubbed upon a burnisher. 



9. Heated by itself in a closed vessel it also gives off a great amount of 

 water. 



Analysis of the Salt. 



10. A portion of the salt was prepared by the foregoing process, and left to 

 dry for several days over sulphuric acid in vacuo. It was then promptly intro- 

 duced into a small glass tube, sealed at its lower end. This tube was inserted 

 into a vessel of boiling water. Its upper end was closed by a cork, through 

 which were fitted two small bent glass tubes, the one connected with a tube of 

 chloride of calcium, arid reaching nearly to the salt, the other connected with 

 the air-pump. By this arrangement a current of dry air could be passed over 

 it, while the water surrounding the tube was kept boiling. A quantity, 1.677.5 

 grammes, of the salt was subjected for half an hour to this process, and lost 

 only 0.002 grammes, or about one-tenth of one per cent.; evidently proving that 

 the salt parts with all its moisture in vacuo at ordinary temperatures. A correc- 

 tion for this amount of water was made in calculating the results of the sub- 

 sequent experiments. 



11. The same portion of the salt was then decomposed by the introduction 

 of water, and an alcoholic solution of chloride of potassium added. The chlo- 



VII. — Q 



