188 ANNUAL OF SCIENTIFIC DISCOVERY. 



The maximum of diseases undoubtedly takes place while the ozonifer- 

 ous current has the ascendency, but they are of a sporadic nature, 

 and are caused by the vicissitudes of weather, electrical influences no 

 doubt playing an important part. The maximum of deaths takes 

 place while the wind is in north points. By far the greatest number 

 of diseases, however, take place in the north-west and south-east 

 points, or at the commencement of ozone periods, and these are chiefly 

 affections of the nervous and muscular systems, from which it would 

 appear that derangements in the nervous and muscular forces take 

 place at the time of transition from the no-ozone and positively elec- 

 tric, to the ozone and negatively electric current of the air. The 

 diseases peculiar to the calm, which is also a no-ozone condition, 

 are of an epidemic nature, such as cholera and choleraic diarrhoea. 

 These results are deduced from twenty-seven hundred and twenty- 

 seven cases of diseases, and eleven hundred and forty-nine deaths, 

 which occurred at Hawarden in a period of ten years. As the south 

 is the higher and ozoniferous current, and the north the lower and 

 no-ozone current of the atmosphere, in a medico-meteorological sense, 

 there ought to be some analogy between the higher strata of the 

 atmosphere and the south wind, and between the lower strata and 

 the north wind ; and observation shows that as regards ozone and 

 deaths they are similar. All who have paid any attention to the 

 atmospheric conditions of a cholera period, must have observed that 

 the readings of the barometer are remarkably high, that they slowly 

 attain their maximum, and that when they begin to decrease they as 

 slowly approach their minimum. While the barometer is increasing, 

 the wind continues to veer from north to north-east and east, until 

 there is a perfect calm. At first the air is clear, and the sky cloud- 

 less. The air becomes less clear, it thickens to haze, and the sky 

 can no longer be perceived. There is no ozone, and the brown test- 

 papers rapidly lose their color. At the commencement of the calm 

 there are a few cases of diarrhoea, and as it continues cases take the 

 character of choleraic diarrhoea, and at last a few cases of cholera 

 occur. The calm continues, the haze thickens, and the cases of chol- 

 era pari passu increase in number and severity. The haze becomes 

 a dry fog, things communicate a gluey sensation to the touch, insects 

 fly about in swarms, and the epidemic reaches its height. The barom- 

 eter, having reached its maximum, begins gradually to drop, the haze 

 becomes more of the character of a fog, and if it can be seen through, 

 cirri will be seen hovering in the higher regions of the air, or moving 

 slowly northwards. The south current is now approaching, the ba- 

 rometer continues to fall, a gentle motion of the air is perceived from 

 south-east. Ozone is detected ; there may be rain ; there may be a 

 thunder-storm. The wind increases in power, and ozone in quantity, 

 and cholera disappears. The rationale of this medico-meteorological 

 process is this : The first part of the process was the north current 

 gaining the ascendency ; and, as it is the land current, bearing the 

 products of decomposition, ozone is reduced to its minimum. While 

 the air keeps in motion, these products do not accumulate in great 

 quantity. The barometer begins to drop. The north current falls 

 back, and is succeeded by the cahn. The products of putrefaction go 

 on accumulating ; there is no renewal of air, and sulphuretted hydro- 



