TRANSACTIONS OF THE SECTIONS. 89 



decreasing readings of tlie barometer and when the readings are below the mean, than 

 with increasing readings and when they are above the mean, and greater when the 

 range of the barometer and the number of its oscillations are above the mean. It is 

 greater when the mean daily temperature and dew-point temperature are above the 

 mean. Ozone is at a minimum with the wind from points north of S.E. and N. W., 

 and at a maximum with the wind from points south of these ; it is also at a maximum 

 when the -svind is above its mean force. AVhen rain is above the mean quantity 

 ozone is also above the mean, and also vni\\ hail ; but it is below the mean with 

 snow and sleet. With fog it is below the mean, above it with cirri, halos, am-ora3, 

 and the zodiacal light, but below it with thunder. It is in greater quantity with 

 negative than with positive electricity. Ozone periods so frequently commence 

 vni\\ the wind from S.E. points of the compass, and so often terminate with the 

 wind in N.W. points, that these may be called their points of commencement and 

 termination. They may also be said to commence with decreasing readings of the 

 barometer and increase of temperatm-e, and to terminate with increasing readings 

 and decrease of temperatm-e. The quantity of ozone is also greater in the nio-ht 

 than in the day. It is greater with new and full moon than duiing the first and 

 last quarters ; and it also varies with the seasons, being greater in the winter and 

 spring months than in summer and autumn. The quantity of ozone varies 

 with the locality ;_ it is greater on the sea-shore than at inland places, and it also 

 increases in quantitj^ with increase of elevation. It is gi-eater in the open country 

 than in towns and villages ; and it is at in drains and cesspools and their vicinity, 

 and, in short, at every place where the products of putrefaction or combustion are in 

 sufficient quantity to decompose it. Although these residts are froniHawarden obser- 

 vations only, they are supported by observations taken at other places. Differences 

 at individual stations may be attributed to purely local causes. Ozone is a highly 

 oxidized body, and it is easily decomposed by oxidable substances. If test-paper 

 prepared with iodide of potassium be exposed in a locality where these substances 

 are at a miuimmu, it wiU in time become brown, and ozone will be at its maximum. 

 If a similar paper be placed in a locality where the quantity of oxidable substances 

 is at its maximum, it will remain white, and ozone will be at a minimum ; and if 

 a brown paper be put in the latter place, it will lose its colour, sulphuretted hydro- 

 gen being the decolorizing agent. On the sea and the sea-shore ozone is at its 

 maximum, because the products of putrefaction are there small in quantity, and 

 the wind which blows over the ocean is the ozoniferous current. On the land the 

 products of decomposition are at their maximum, hence the current of air that 

 passes over it is non-ozoniferous. Indeed aU the conditions of an ozone period are 

 those of the equatorial or ocean cun-ent of the atmosphere, and the conditions of a 

 no-ozone period are those of the polar or land current. 



Medico-meteorological results give the maximum of diseases with the ozoniferous 

 current, and the maximum of deaths with the no-ozone current, but the diseases 

 may be attributed rather to the vicissitudes of weather than to ozone. As the land 

 or polar current of the au- is the lower strata in motion, and the ocean or equatorial 

 current the motion of the higher sti-ata, there ought to be an analogy in a medico- 

 meteorological sense between them, and so we find that the maximum of deaths takes 

 place in the lower strata with minimnm of ozone, and the minimum of deaths in 

 the higher strata with maximum of ozone. The calm is also a no-ozone period. 

 During continued calms the products of putrefaction accumulate in the lower strata 

 of the atmosphere and produce diseases of an epidemic nature. A cholera period 

 is a calm and a no-ozone period ; and cholera periods tei-minate with the setting 

 in of the ozoniferous current. In conducting ozone observations, it must be borne 

 in mind that light causes coloration of the test-papers, and that moisture, sul- 

 phuretted hydrogen and anmronia cause loss of colour. 



On Sulphuretted Hydrogen as a Product of Putrefaction. 



By Dr. Moffat. 



The author had enclosed portions of animal and vegetable matter in tin boxes, 



and through slits in the lids, test-papers prepared with carbonate of lead and vnth 



iodine were introduced to half their length. The action of sulphuretted hydrogen 



•was decisively shown, both in the case of the animal and the vegetable matters. 



