244 



Prof. T. Oarnelley and Mr. W. Mackie. 



Tlie above results refer only to ordinary week days, and do not 

 include Saturday and Sunday, which are not normal days in a large 

 town. On several occasions an important decrease was noted towards 

 the noon of Saturday, no doubt due to the stoppage of the boiler fires 

 at the mills and factories. This is shown by the following numbers, 

 which include all the cases observed : — 



1885, November 7th. 



November 21st. 



November 28th. 



Time. 



Organic 



Time. 



Organic 



Time. 



Organic 



matter. 



matter. 



matter. 



10 '30 A.M. 



8'9 



11-30 A.M. 



12-7 



10'30 A.M. 



10 -2 



12 15 p.m. 



8-1 



1 '30 p.m. 



10-6 



12-15 A.M. 



8-3 



1 -15 P.M. 



8-3 











A relation to the products of the imperfect combustion of coal is 

 also indicated by the much higher averages obtained for outside air 

 in the centre of Dundee, as compared with the suburbs and with Perth, 

 thus : — 





Dundee (town). 





No. of " 

 cases. 



Lowest. 



Highest. 



Mean. 



Organic matter (O required per "1 

 Carbonic acid (per 10,000 vols. 1 



46 

 32 



1-7 



2 2 



16-8 

 5-6 



8-9 

 3-9 







Dundee (suburbs). 





No. of 

 cases. 



Lowest. 



Highest. 



Mean. 



Organic matter (O required per \ 



1,000,000 vols, of air) J 



Carbonic acid (per 10,000 vols. \ 



10 

 5 







1-7 



5-6 

 3-5 



2-8 

 2-8 



