McWeeney — Cases of Carbon Monoxide Asphyxiation. 227' 



after the couple retired to the room (that is, till 12 o'clock), and 

 then became extinguished. 



The problem may, therefore, be stated thus : — 

 A room has a capacity of 1,000 cubic feet, and the atmosphere 

 is changed once every 2*25 hours. Its original composition may 

 be assumed normal (790 vols, of N, 209-6 of O, and 0'4 of C0 2 ). 

 C0 2 is introduced (a) by combustion of coal-gas, (b) by respira- 

 tion: (a) goes on for only 2 hours (at the rate of 5 feet per 

 hour), and delivers 2-5 cubic feet of C0 2 per hour (being at the 

 rate of half a foot of C0 2 per foot of gas burnt ; (b) continues all 

 through the experiment, which lasts from 10 p.m. till 6 p.m. nest 

 day (20 hours), and delivers 1*2 cubic feet C0 2 per hour (0'6 per 

 individual). 



Coal-gas is delivered into the room during the last 18 hours of 

 the experiment at the rate of 5 feet per hour. It contains 16 per 

 cent, of carbon monoxide. 



Eequired — (1) The maximum percentage of C0 2 that will be 

 reached in the atmosphere. 



(2) How long it will be before it will be reached. 



(3) The maximum percentage of CO which will be reached 

 during the experimental period. 



(4) How long it will be before the maximum percentage is 

 reached. 



It is assumed that the entering air is normal in composition, 

 and that it at once and completely mingles with the air already in 

 the room. 



I have submitted this problem to a competent mathematical 

 authority, who reports as follows : — The C0 2 introduced attains its 

 maximum at the end of the first 2 hours, when it is 4*9 cubic feet. 

 It then decreases during the 18 hours to practically 2*7 cubic feet. 

 The change is more rapid at the beginning and very gradual 

 towards the end. It is 3'51 cubic feet at the end of 2*25 hours, 

 and 3 cubic feet at the end of 4*5 hours, so from this it changes 

 very little. 



As regards the coal-gas, the percentage goes on increasing alii 

 the time, tending towards the theoretical maximum which would 

 be 11-25 cubic feet, containing 1-8 cubic feet of CO. That 11*25 

 cubic feet is the maximum is shown by the fact that the wastage 



