82 Transactiaas of the 



nic nitrite (NH^NOg), the product of oxidation by ozone. 

 Still keeping the glass plate in its place, the jar should be 

 inverted over a pneumatic trough to remove the phosphorus. 

 The gas should now be washed free from any vapour of phos- 

 phorus or phosphorous acid, when the contents are ready 

 for experiment. By none of the foregoing, nor by any other 

 process at present known, can ozone be procured ft-ee from 

 admixture with other gases, but always in a state of me- 

 chanical mixture with from 50 to 200 times its volume of 

 oxygen. It seems possible that the production of ozone by 

 the oxidation of phosphorus in moist air may be thus ex- 

 plained. The phosphorus, while uniting with one portion 

 of oxygen to form phosphorous acid, frees a corresponding 

 portion as an allotropic modification known to us as ozone. 

 A similar theory will account for the bleaching properties of 

 sulphurous anhydide (SOg) in presence of oxygen, one portion 

 of oxygen going to the oxidation of the sulphurous acid, 

 while another, as ozone, oxidizes the other body present. 

 This theory is founded on Schonbein's hypothesis as to the 

 constitution of ordinary oxygen. However ozone is prepared 

 its properties are always identical. This identity has been 

 proved {Phil. Trans. 1855 and 1860), by Dr. Thomas Andrews 

 with regard to the ozone produced by statical and dynamical 

 electricity and the oxidation of phosphorus in moist air. 

 He bases his conclusions upon the following properties, which 

 in all cases of ozone are identical, and are not common to 

 nitrous acid (Ng^s)? chlorine, or any other compound which 

 might be mistaken for ozone : — (1) The oxidation of mercury, 

 silver, or other metals. (2) The ozonized air is destroyed 

 by being passed over peroxide of manganese (MnOo). (3) The 

 action of heat destroys it, which certainly would not be the 

 case with nitrous acid or chlorine, which he verified by ex- 

 periment. These results were also confirmed by MM. Soret, 

 Claus, and Yon Babo in such a way as to utterly demolish 

 the theory of Williamson and Baumert that ozone is a 

 peculiar trioxide of hydrogen (H2O3). Ozone will be found to 

 difier considerably from oxygen in having a singular metallic 

 smell, somewhat resembling hypochlorous acid (HCIO). It 

 is poisonous — mice and other small animals will expire in an 

 atmosphere containing even such a small proportion as -g-oVo 

 of ozone. Two millegrammes or -^ of a grain is sufficient 

 to kill a rabbit. It has been asserted that the cause of death 

 by a stroke of lightning is due to suffocation by a large 

 amount of ozone generated around the person struck. Even 

 when largely diffused in the air it causes an unpleasant sen- 



