254 SCIENCE FROM AN EASY CHAIR 



infrequently, on arriving at the seaside, sniff up the odours 

 of decomposing seaweed (containing a little iodine), and 

 think they are smelling the "ozone." It is doubtful 

 whether enough ozone is ever present in the atmosphere 

 under simple natural conditions to affect even a highly- 

 sensitive nose. But it is easy to produce enough by 

 passing air over a silent electrical discharge to fill a 

 large room with its peculiar smell. Whether it really 

 is of benefit to the human being who inhales a properly 

 limited percentage of it seems not to have been clearly 

 decided by experiment, although both in London and 

 the United States of America there are enterprising 

 medical men who are convinced of its value and are 

 using it. It would certainly seem that if the peculiar 

 benefit which is often derived from sea air or from 

 mountain air is due to the presence of this extra oxygen 

 in such air, then nothing can be simpler or more rational 

 than to introduce the proper and useful percentage of 

 ozone into the air of specially-arranged chambers in 

 London and other large towns, so that we can visit or 

 even inhabit them and breathe ozonised air at will without 

 going on a journey for it. 



But it is a remarkable fact that, as with various 

 natural so-called " mineral waters," so with various " airs " 

 which people find beneficial no one has yet clearly and 

 decisively shown, in the first place, whether they exert 

 any chemical effect of a special kind on the people who 

 seem to benefit by drinking the one or breathing the 

 other ; still less has any one shown what is the particular 

 chemical ingredient of the air or of the water of any given 

 resort which exerts the beneficial effect attributed to that 

 air or that water. 



The air in different localities differs most obviously 

 and importantly in four particulars, namely, as to whether 

 it is still or windy, whether it is cool or hot relatively to 



