446 Prof. Schonbein on the Connexion of 



My experiments have shown that distinct tracesof nitric acid are 

 foi'med during the combustion of phosphorus in atmospheric air, 

 and as the ozonized oxygen is capable of oxidizing the atmospheric 

 nitrogen to the same acid in the presence of a fixed base, it seems 

 to me possible that even in the decay of non-nitrogenous sub- 

 stances in atmospheric air under certain circumstances, for ex- 

 ample the presence of alkaline bases, small quantities at any rate 

 of nitrate are formed ; and, if I mistake not, Theodoi-e von Saus- 

 sure, a very accurate observer, has stated that this is the case. 



From the great importance to agriculture which the nitrates 

 have recently acquired, I need scarcely remark how desirable it 

 is to answer by decisive experiments, the question whether ni- 

 trates are produced in the decay of nitrogenous organic sub- 

 stances under the conditions mentioned. If the question were 

 answered in the affirmative, we should become acquainted with 

 a new source from which plants might derive the requisite ni- 

 trogen; that is, we should know that the fertilizing property 

 of non-nitrogenous organic substances did not arise from their 

 carbon merely, but also from their capacity of determining the 

 atmospheric oxygen to the oxidation of atmospheric nitrogen, 

 that is, to the formation of nitrates. 



Respiration is, like decay, in a chemical sense a slow com- 

 bustion effected by atmospheric oxygen; and since we must 

 deny ^ to this oxygen, without it has been pre^ously changed into 

 the O condition, the property of producing any oxidation, we 

 are compelled to assume that blood also contains a substance 

 which, like the above-mentioned mushroom juice, can convert 

 into ; and therefore that the chemical part of i-espiration 

 is a process which depends on an allotropy of the inspired oxygen ; 

 on this subject I have elsewhere developed my views at greater 

 length. 



From the preceding considerations, it is clear that a large 

 number of chemical phsenomena must be considered to be cata- 

 lytic, or actions by contact, and we may assume that their ulti- 

 mate cause is an allotropy of oxygen, whether these actions 

 depend on an oxidation or the reverse. 



Although it is very remarkable that the majority of the 

 actions by contact hitherto made known are those in which 

 oxygen plays an essential part, yet there are also others in which 

 this element plays no part. Of these, persulphide of hydrogen 

 = HS^ is an example. This substance, according to Thenard, 

 can be decomposed into sulphur and HS by a series of sub- 

 stances which do not combine with either the one or the other 

 of the constituents of the HS'^. 



The immediate cause of this decomposition is certainly quite 

 unknown to us at present. But if, in my opinion, it has become 

 very probable that many substanpes decompose peroxide of Ijy- 



