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abounding in the summer months, when the decay of animal and 
vegetable substances goes on most rapidly, and greatly interfering 
with its salubrity. In the case of Bath, in particular, these 
noxious particles would not be sufficiently carried off, in conse- 
quence of the hills and the confined situation of the town, checking 
free circulation, as just spoken of. In an Address by Dr. Rumsey, 
on the subject of Health, to the Social Science Association, in 1868, 
it was stated, as a demonstrated fact, that—‘‘ Town air, even in 
its best conditions, contains subtle poison, from which the airy 
upland and the breezy shore are free, and that it also wants some 
elements of nutrition and purification which the latter supply.” 
The sources from which these impurities arise are manifold, and 
may easily be conceived by all who have ever resided in towns, 
and witnessed the trade operations which are constantly going on 
in them to meet human requirements in a highly artificial state of 
soeiety. One of the great purifiers of the air from such contami- 
nating influences is thought to be Ozone, a substance of which we 
have as yet very insufficient knowledge, and the amount of which, 
present in the air at any particular time, it seems difficult to 
determine, from the usual test-papers not being always trust- 
| worthy, and the necessary precautions, in order to avoid error 
from the influence of light and the differences in the force of 
the wind, not being sufficiently attended to. * 
It is, however, generally allowed that ozone is a substance 
abounding much more in some places than others, especially much 
more in the country than in towns. There is a good deal said on 
this subject in an Address delivered before the Royal Society of 
Edinburgh, on December 22, 1873, by Dr. Andrews, in which he 
treats of ozone at great length, and from which I beg to quote one 
or two passages bearing upon the point in question.t+ 
“‘ Ozone,” he remarks, “is rarely found in the air of large towns, 
* See “‘Daubeny on Ozone,” p. 8, &c. 
+ See “ Nature,” vol. ix., p. 347. &c., and especially p. 366, 
2 »i¢ 
