223 
Hence we may conclude that the combustion of coal and 
the respiration of animals exert no appreciable influence on 
the quantity of carbonic acid contained in the town air of 
Manchester collected in an open situation ; gaseous diffusion 
and the great motions of the atmosphere serving completely 
to disperse the millions of tons of this gas which every year 
are evolved by the above-mentioned causes in this neigh- 
bourhood. 
I may add the following determinations, made in the same 
way, of the carbonic acid contained in the air of closed 
inhabited spaces : — 
1'. Chemical Theatre, Owens College, during lecture. 
Temp. 9° C. Bar. 755 mm. CO, in 10,000 of air 9’5 vols. 
2. Chemical Laboratory, Owens College. 
9 o’clock a.m. Temp. 17‘5° Bar. 733'5. CO, = 8’3 vols. 
in 10,000. 
12 o’clock Temp. 19‘5° Bar. 733 5. CO 2 = 9 , 0 vols. in 
10 , 000 . 
3. Large bedroom, with invalid and attendant. 
Temp. 12°. CO, in 10,000 vols. of air = 7-4. 
4. Parlour (capacity 3,000 cubic feet), four persons, three 
gaslights, good fire. 
Temp. 19°. CO, in 10,000 vols. of air = 13‘2. 
5. Ditto ditto. 
Temp, 18°. C0 2 in 10,000 vols. of air = 136. 
G. Ditto ditto. 
Temp. 15°. CO, in 10,000 vols. of air = 1 4*5. 
7. Crowded meeting-room of artisans in Penny’s Mill, Gay- 
thorn — Guardian Schools — 1,000 persons. 
Temp. 18°. C0 2 in 10,000 vols. of air = 36 5. 
C0 2 in 10,000 vols. of air = 35 5. 
