516 M. Millon on Nitrification. 



the porcelain it would have been decomposed into oxygen and 

 chlorine, which would have liberated some iodine, whereas ozone 

 would at that high temperature be converted into ordinary 

 oxygen, which would be without action on the iodide. 



To determine the quantity of ozone, a given weight of the 

 mineral was triturated in a mortar with iodide of potassium, and 

 the liberated iodine estimated by means of hyposulphite of soda. 

 In this way its quantity was found to amount to 0*02 per cent. 



The ozone doubtless exists ready formed in the mineral, as 

 the following experiment shows that fluor-spar can absorb ozone. 

 17 grms. of a specimen of fluor-spar, which by a preliminary ex- 

 periment was found to contain 0*00011 per cent, of ozone, was 

 exposed for six hours in a current of strongly ozonized air, and 

 at the expiration of that time was found to contain 0001 per 

 cent. Pieces of pumice exposed in a similar manner to ozonized 

 air were found to absorb ozone. 



Millon has communicated the following observations on nitri- 

 fication*, which in another form have been already made by 

 Schdnbeint- Under the conditions of high temperature, nitre is 

 always produced with regularity, provided a humus product, an 

 ammoniacal salt, and a mixture of earthy carbonates are present. 

 The solid mass must further be constantly moistened and exposed 

 to the air. 



The necessity of the presence of humus is not at once appa- 

 rent, and yet it gives a clue to the process. The alkaline humate 

 which is formed energetically absorbs oxygen, and this oxidation 

 is transferred to the ammonia. The part which humus plays is 

 evident from the fact that it may be replaced by other oxidizable 

 substances, such as phosphorus. When a stick of this substance 

 is placed in a large glass globe and half covered with ammoniacal 

 water, a slow combustion of the phosphorus soon commences and 

 incites that of the ammonia. After some time nitrate of am- 

 monia is found in the liquor. The ammonia in this experiment 

 may be replaced by carbonate of ammonia, but not by the hy- 

 drochlorate or the sulphate. It appears, therefore, that nitrifi- 

 cation takes places in the atmosphere between the emergent part 

 of the phosphorus, the water, the air, and the ammonia. 



Millon also shows, as had already been done by TuttleJ, that 

 copper can be similarly used to effect nitrification. 



Ammonia is not the only substance which can be thus oxidized. 

 When a stick of phosphorus is placed in a colourless solution of 

 a manganese salt, it speedily becomes of a beautiful violet tint. 



* Comptes Rendus, October 8. 



t Phil. Mag. vol. xiii. p. 440. 



X Liebig's Annalen, voi. ci. p. 283. 



