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ROYAL SOCIETY OF CANADA 



practice lie has noted many cases of a like nature to the ones just detailed. 

 He also has tried increasing the moisture in the atmosphere with exceed- 

 ingly good results. 



Having established the fact of the deleterious action of an atmos- 

 phere containing too little moisture upon the human organism, your 

 attention is invited to the appended tables wherein are shown a series of 

 average observations. 



In speaking of the moisture, or more correctly the amount of mois- 

 ture, contained in the atmosphere, it ought to be noted that too dry air 

 is unpleasant to breathe, saturated air when warm is unbearable, e.g. 

 80 °F. — the most comfortable is when the air contains about 70-75 per 

 cent of moisture necessary to saturate it. 



Average rel. humidity 



Average temp, (indoor) 



Average rel. humidity (indoor) — win- 

 dows closed 



Average rel. humidity (indoor) — win- 

 dows open 



80.3 

 65° 



45 



58 



In these tables will be noted first the constancy of the indoor tem- 

 perature — this is as it should be in a private house, such as the one 

 in which all these observations were made. The outdoor temperature is 

 tnot recorded, but during the months of January, February and part of 

 March, it is often 0°F. or well below, on the average. 



Knowing then that if we warm a given quantity of air completely 

 saturated with moisture at the initial temperature it no longer remains 

 saturated, we can readily see what an enormious difference in the relative 

 humidity is entailed by heating the outside air registering 0°F., or below, 

 to a temperature of 64 °F. 



The effects of allowing some of the unheated outside air to enter 

 the house, are plainly visible when comparing the series of relative 



