produced by Catalytic Bodies. 199 



oxidation being carbonic acid. The NO4 or NOg acts in these 

 cases clearly by aiding the compound ready to oxygenate, but 

 which, under the conditions, has not sufficient power to de- 

 compose the nitric acid without additional aid. The same ex- 

 planation probably applies to the singular discovery of Pro- 

 fessor Graham*, that the addition of NO4 to non-accendible 

 phosphuretted hydrogen renders it inflammable. In this case 

 the two combined affinities produce the union of oxygen 

 with one of the bodies. The presence of the small quantity 

 of another compound of phosphuretted hydrogen in the spon- 

 taneously accendible gas, as described by Leverrierf and by 

 ThenardJ, may probably act in the same manner. 



The action of this compound (PHc2) corresponding to ami- 

 dogen (NH2) may be conceived so to disturb the attraction of 

 the phosphorus to the hydrogen in the gas PH3 as to produce 

 the inflammability. Both the elements of this gas are highly 

 combustible, uniting with oxygen at a low temperature. 

 Their mutual attractions are sufficiently strong to prevent the 

 oxygen breaking up this union ; but when the second body 

 is present, the desire of PHg for another atom of hydrogen 

 may be supposed so far to draw the third atom of hydrogen 

 from the PHg, that oxygen has now the power to unite with 

 the two inflammable elements. In disturbing the existing 

 equilibrium, it is presumed to act just as a spark would do by 

 elevating the already strong affinities of the two elements for 

 oxygen. When a solution of hypochlorite of lime is poured 

 into a solution of muriate of ammonia in excess, a very pun- 

 gent volatile compound results, which has no bleaching pro- 

 perties, and therefore does not contain hypochlorous acid. 

 The decomposition is expressed by the equation NH4 CI + 

 CaO, CIO = NH2 CI + 2HO + Ca CI. The volatile com- 

 pound NHg CI has an affinity for hydrogen in order to pass 

 into NH4 CI. This body was well-fitted to test the view of the 

 cause of the inflammability of phosphuretted hydrogen (even 

 supposing PH2 is not spontaneously inflammable, as it is 

 stated to be by Thenard), On placing gas (which had en- 

 tirely lost its inflammability by standing several days over 

 water), in contact with the above mixture, in about an hour it 

 acquired the property of smoking strongly in the air, although 

 it did not inflame spontaneously. This showed that the 

 affinity of PH3 for oxygen was much elevated, although the 

 attraction was not sufficient for inflammation. 



* Trans, Royal Soc. Edin. vol. xiii. p. 5. 

 t Ann. de Ch. et de Phys. Ix, 174. 



X Comptes Rendus des Seances de VAcademie des Sciences, t. xviii. 

 pp. 252, Ol-l ; t. xix. p. 313. 



