246 



Prof. T. Carnelley and Mr. W. Mackie. 



for a certain length of time, and then making a determination of the 

 carbonic acid and organic matter in the air thns vitiated. The 

 following is an example of a number of experiments all giving similar 

 results : — 





C0 2 per 

 10,000 vols. 



Organic matter 

 (vols, of O required 

 per 1,000,000 vols, of air). 



After the gas bad been burn- 1 

 After the gas bad been burn- 1 



4-3 

 11-0 



14-8 



10*6 TEacb of these is 



11 *8 ^ e mean °^ 

 <j two nearly con- 



.., R | cord ant experi- 



11 ' a t. ments. 



The combustion of gas may therefore be considered too perfect 

 to produce any appreciable effect. What result is obtained may 

 safely be set to the credit of sulphurous acid. 



The above remarks apply to Dundee gas, which is considered to be 

 exceptionally pure and free from sulphur. 



(6.) Combustion of Oil Lamps. — The effect of burning oil lamps is 

 much more marked than that of the combustion of gas. This was 

 determined in a manner similar to that in the case of coal-gas, the 

 experiments being carried out in the same practically air-tight room 

 as before. The following will serve as an example : — 



Before burning of oil lamps 



After one lamp bad been burning half an hour, 1 

 the lamp was found to be smoking slightly . . J 



Ditto after one hour, lamp found burning clear . . 



After the first lamp had been burning one and a 1 

 half hour, and a second lamp half an hour, the > 

 second lamp was found smoking slightly .... J 



Ditto after first lamp had been burning two hours, "1 

 and the second one hour, both lamps found j» 

 burning clear j 



Organic matter (O required per 

 1,000,000 vols, of air). 



Each of these 

 is the mean 

 of two very 

 closely con- 

 cordant de- 

 terminations. 



12-3 

 14-6 



16 -7 



18-1 J 



In all cases the lamps were burning paraffin oil and were turned on 

 as full as possible without smoking. 



(7.) Respiration. — Respired air gives a higher result than un- 

 rsspired air at the same time, though much less than was anticipated. 



The effect of respiration was determined as follows : — The observer 

 worked in the small air-tight room previously referred to. This was 

 first ventilated with outside air and then closed, and at the end of 



