148 The Literature of Ozone, etc. 



state, that when zinc in fine division is shaken up with water 

 and air, the oxygen of the air causes an energetic oxidation of 

 the zinc. As a result of this oxidation, the oxygen molecule is 

 divided, one atom going to the zinc and the other being for an 

 instant set free. This atomic oxygen brings forth very energetic 

 oxidations, oxidizing indigo to isatin, forming hydrogen perox- 

 ide, decomposing potassium iodide and developing nitrous acid. 

 The latter speedily disappears, being oxidized by the peroxide 

 of hydrogen to nitric acid, while the excess of peroxide of hydro- 

 gen, which appears to be the most abundant product of the 

 reaction, is decomposed by the zinc. 



It might be supposed that these phenomena are due to the 

 oxidation of nascent hydrogen set free by the decomposition of 

 the water itself. But this is not the case. Pure zinc does not 

 decompose water, and ordinary zinc decomposes it in too small 

 an amount to explain the observed phenomena. This being the 

 case, zinc acts in a manner analogous to phosphorus, viz. : 

 Zn+ H 2 + 2 = ZnH 2 2 + 



An experiment recently performed by Kappel can be best ex- 

 plained in like manner. On agitating Cu with an alkaline solu- 

 tion and air, he obtained the reaction both for ozone and hydro- 

 gen peroxide, but not the nitrous reaction. His test-papers sus- 

 pended above the liquid became blue, but were immediately de- 

 colorised, a result attributed to the decomposition of the ozone 

 first formed, by the peroxide of hydrogen. For on passing a 

 current of air so as to remove the ozone, the hydrogen peroxide 

 reaction was readily obtained. (Berl. Bench te, XV, 2359.) 



III. Liquefaction and Color of Ozone. 



The most important discoveries during the past three years 

 concerning the properties of ozone, are those made by Haute- 

 feuille and Chappuis. They found that ozone is a blue gas, the 

 color appearing sky-blue even when only so much ozone is present 

 as is obtained in the ozonation of the oxygen contained in a tube 

 a metre in length, by the silent discharge. Furthermore, they 

 found that under very great pressures the condensed gas becomes 

 indigo blue. If the pressure is increased to 75 atmospheres and 

 then suddenly relieved, a dense Avhite cloud is formed, showing 

 the beginning of liquefaction, whilst the same phenomenon does 



