OZONE. 353 



atom, and so disappear as ozone, two-thirds of its weight 

 remaining as oxygen. 



It is to this peculiarity that ozone owes the properties 

 which render it so important to our welfare. We are indeed, 

 as yet, in no position to theorize respecting this element, 

 our knowledge of its very existence being so recent, and our 

 information respecting its presence in our atmosphere being 

 of still more recent acquisition. 



Indeed, it is well remarked by Mr. Heaton, that we 

 had, until quite lately, no reason for confidently adopting 

 Schonbein's view that ozone exists in our atmosphere. The 

 test-papers which Schdnbein made use of turned blue under 

 the influence of ozone, it is true, but they were similarly in- 

 fluenced by other elements which are known to exist in our 

 atmosphere, and even the sun's rays turned them blue. 

 However, Dr. Andrews has shown how the character of the 

 air producing the change can be further tested, so as to 

 render it certain that ozone only has been at work. If 

 air which colours the test-papers be found to lose the pro- 

 perty after being heated, the change can only be due to 

 ozone, because nitrous and nitric acids (which have the 

 power of colouring the test-papers) would not be removed by 

 the heat, whereas ozone is changed by heat into oxygen. 



Once we are certain that ozone exists in the air, we 

 must recognize the fact that its presence cannot fail to have 

 an important bearing on our health and comfort ; for ozone 

 is an exceedingly active agent, and cannot exist anywhere 

 without setting busily to its own proper work. What that 

 work is, and whether it is beneficial or deleterious to our 

 selves, remains to be considered. 



In the first place, ozone has immense power as a disin 

 fectant It decomposes the products emanating from putre- 

 fying matter more effectually than any other known element. 

 Perhaps the most striking proof ever given of its qualities in 

 this respect is that afforded by an experiment conducted by 

 Dr. Richardson a few years ago. 



He placed a pint of blood taken from an ox in a large 



2 A 



