4 
DR. W. MARCET ON A CHEMICAL INQUIRY INTO 
Strastiirg. 
Ste. Croix. 
Ten lowest temperatures. 
Ten liigliest temperatures. 
Ten lowest temjreratures. 
'J’en highest temperatures. 
Tempera 
tures. 
COo. 
Tempera¬ 
tures. 
CO.. 
Tempera- 
ture.s. 
COj. 
Tempera¬ 
tures. 
CO.. 
r°rjO 
0-393 
is'-eo 
0-354 
8-75 
0-393 
16-00 
0-387 
9-60 
0-413 
15-40 
0-342 
9-00 
0-385 
16-00 
0-447 
9-60 
0-370 
14-20 
0-396 
9-.30 
0-391 
15-90 
0-412 
10-00 
0-390 
14-00 
0-350 
9-40 
0-422 
15-90 
0-376 
10-50 
0-390 
13-80 
0-358 
9-50 
0-388 
15-90 
0-423 
10-80 
0-396 
13-80 
0-377 
9-50 
0-374 
15-80 
0-413 
10-90 
0-398 
13-70 
0-348 
9-55 
0-374 
15-50 
0-404 
11-20 
0-394 
13-50 
0-379 
9-90 
0-394 
15-30 
0-386 
n-20 
0-382 
13-40 
0-361 
10-10 
0-418 
14-90 
0-427 
12G0 
0-390 
13-40 
0-358 
10-30 
0-421 
14-50 
0-.391 
Mean 10-59 
0-392 
14-08 
0-362 
9-53 
0-396 
15-57 
0-406 
It follows from this Table that the experiments made at the ten lowest temperatures 
at Strasburg yield an increase of carbonic acid of 7'6 per cent, over the experiments 
made at the ten highest temperatures. This is just what might have been expected 
from the effect of the cold. At Ste. Croix, however, the conclusion is very different, as 
at that station there is a slight excess of 2’4 percent, carbonic acid for the ex23eriments 
made at the hio-hest temperature over tlie mean carbonic acid found at the lowest tern- 
peratures at that same station. Moreover, if we compare with each other the mean 
Aveights of carbonic acid expired at the ten lowest temperatures for the two stations, 
they will be found nearly exactly the same (0‘392 and 0'396), while for the ten highest 
temperatures there is much more carbonic acid expired at Ste. Croix than at Strasburg 
(0‘406 and 0'3G2), the increase being by no less than 10‘8 per cent. This appears at 
first sight quite unaccountable, although I think it can be satisfactorily explained. 
There AAms clearly some influence on the experiments at Ste. Croix connected with 
the highest temperatures which was absent at Strasburg. That influence I believe to 
be a lower state of relative humidity of the air, which, by producing increased perspi¬ 
ration and increased evaporation at the lungs, exerted a cooling action on the body, 
thus necessitating an increase of animal combustion. It is true that the atmosphere 
was warmer, but this circumstance failed to compensate for the cold produced by 
increased perspiration and evaporation. 
This explanation appears to me to account satisfactorily for the increase of carbonic 
acid observed at the higher station : it was not due to the fall of atmospheric pressure, 
but to increased dryness of the atmosphere, acting precisely in the same way as an 
accession of cold would have done. 
