Manchester Memoirs, Vol. Ivii. (191 3), No. 14. 3 



inside the tube leading from the fan through which an 

 electric current passed to provide the required tempera- 

 ture to the air. 



The alternate breathing of dry and damp air was 

 made by three different persons, who breathed first the 

 damp and then the dry air about 56' Fahrenheit and 

 afterwards damp and dry air at blood heat {cjW' Fah.) ; in 

 each case the " damp " air was, as nearly as possible, 

 saturated with moisture at the two different temperatures. 



In these experiments the personal element enters to 

 a large extent, and in one of the persons breathing these 

 different atmospheres there was in some of the experi- 

 ments no difference in the CO2 present in the exhaled 

 air between the damp and dry air (cold air). He says on 

 these occasions he suffered from cold, and this he thinks 

 may have accounted for it, but as a whole, even in cold 

 air, there is with him on the average a larger percentage 

 of CO2 in the dry than in the damp cold air, and a 

 considerable difference with him between the damp and 

 dry luarvi air. 



The total average increase for the three persons on 

 the dry over the damp cold air amounted to 4 [)er cent., 

 and on the dry over the damp warm air of 7'53 per cent. 



The following gives the figures obtained for each 

 person under the different conditions : — 



