32 •'• Lindhard. 



rather incomplete, made at too great intervals; nevertheless they 

 give a somewhat reliable picture of the changes of temperature on 

 the days concerned. It will be seen, firstly, that the curves for the 

 two temperatures are not parallel, also that the summer and winter 

 curves vary distinctly; and on closer examination this difference 

 appears to be: hi summer in the morning measurements the tw^o 

 temperatures are almost equally high, about ^^65''; in winter the 

 rectal temperature at the same time of day is nearly the same as 

 in summer; but the mouth temperature is considerably lower, about 

 357°. The distance between two curves of the same set when 

 approximately parallel is also generally greater in winter than in 

 summer. The reason is that the summer measurements were made 

 while sailing, at a time when all rooms were rather well-heated 

 from the machine of the ship, but in winter the heating of the 

 room by means of a petroleum-oven was, as a rule, insufficient, 

 and the temperature in the cabin especially in the morning was 

 generally below zero. 



The greatest differences between two simultaneous temperatures, 

 due to staying in the open air, are nearly the same summer and 

 winter, reaching about 2°, but they are produced in different ways. 

 In summer they are practically always due to fall in the mouth- 

 temperature; there is even several times a fall of the rectal temper- 

 ature at the same time; in winter the fall in the temperature of 

 the mouth is less well-marked, but at the same time there is a rise 

 in the rectal temperature. 



This comes from the fact, that while sailing -we would sit on 

 the deck for hours with the head uncovered at a temperature of 

 about 2° C, but in winter one was constantly in movement, and 

 except for the central part of the face the head was covered by a 

 helmet-shaped camel's hair cap and wind-tight hood; consequently, 

 the cold air could not act directly, as in summer, on the skin of 

 the chin and neck. All measurements were made indoors, a fact 

 more likely to contribute to equalize than to emphasize the differ- 

 ence between curves of one set. 



Diagram V shows directly the dependence of the temperature 

 of the mouth on the air temperature. The two upper curves are 

 derived from measurements made every second day, about 1045 a. m., 

 2 hours after breakfast in a heated room. In the whole series there 

 is but one real disagreement, where the mouth temperature is lower 

 than was to be expected from the air temperature. I have not 

 noted down what I had been doing just before the measurement; 

 but a departure in this direction would be readily explicable, if, shortly 

 before the reading, I had been in a cold room or in the open air. 



