152 J- Lindhard. 



constant, with exception of a couple of experiments. The relatively 

 high frequency on ^'^'/.s Avas due, as mentioned, to a desire to defæ- 

 cate during the experiment and this should perhaps be omitted. 

 The low value on the last day is due probably to the influence of 

 the cold. The two curves only show an indication of symmetry 

 towards the end; for the rest, the course of the curves, as also the 

 single rises and falls are apparently without connection \vith the 

 barometric curve. 



The even respiration-curve is still found in November; but the 

 regularity is broken by a couple of strongly divergent values. I am 

 not clear as to the reason for these deviations. The barometric 

 curve in this series again shows somewhat greater variations but 

 these have obviously no connection with the deviations mentioned 

 in the frequency. Nor are the curves symmetrical here, they seem 

 rather to indicate parallelism. 



In the winter experiments, January 1908, we again meet with 

 symmetrical curves, which are the same as the first-mentioned not 

 only in the main but even in details. The variations are greater 

 than in any other series of morning experiments and this applies 

 to both curves. The striking deviation from the rule, which occurs 

 in the respiration-frequency of ^-^/i, can only be imagined as arising 

 from the possibility of an error in counting, due to extreme sleepi- 

 ness on the day in question. With regard to the high frequency on 

 ^^'i it may be remarked, that the barometric fall on ^^/i lasted till 

 late in the night, and that the rise thus occurred only a few hours 

 before the experiment. This experiment in many respects resembles 

 the experiment on ^/12 in the preparatory series. 



The features of the Copenhagen experiments are quite the same 

 as those of the Greenland experiments at the same time of year. 

 The symmetry between the two curves is unmistakable. It is best 

 expressed in the first half of the period, as my mode of living was 

 just as regular as in Greenland. In the latter half my bed-time 

 especially was less regular; but it is only in one case that imperfect' 

 sleep had anything to do with the result, in experiment No. 132, 

 which is divergent in several regards. 



It results from the experiments, therefore, that the respiration- 

 frequency and the air-pressure vary in an opposite direction ^ This 

 relation is distinct in the Greenland winter and spring experiments, 

 as also in tlie Copenhagen experiments, more difficult, in part im- 

 possible to recognize in the Greenland summer experiments. Now 

 the barometric fluctuations are less in summer than in winter; but 



^ The same was found by Mosso in sleeping marmots: Der Mensch a. d. Hoch- 

 alpen. Leipzig 1889. Chap. XIX. 



