Comparative Air-Analyses 



93 



Table 53. Analyses of outdoor air made at the Nutrition Laboratory. Series 2 Cont'd. 



[All samples were taken from the west side of the laboratory.] 



Date. 



1910. 

 Dec. 15 



Dec. 19 



Dec. 20 



Dec. 22 



Dec. 23 



1911. 



Jan. 18 



Jan. 20 



Jan. 21 

 Feb. 10 



Time. 



9h43m a-m . 



10 42 a.m. 



11 04 a.m. 

 11 53 a.m. 



2 20 p.m. 



9 41 a.m. 



10 37 a.m. 



11 32 a.m. 

 2 04 



10 38 



11 38 a.m. 

 9 42 a.m. 



p.m. 

 a.m. 



3 10 p.m. 



4 14 p.m. 

 9 31 a.m. 



10 44 a.m. 



11 52 a.m. 

 3 29 p.m. 

 9 17 a.m. 



0.0 

 6.4 

 0.8 



766.35 

 754.60 

 75S.00 



Wind. 



Light, SE. , 

 Brisk SW... 

 Light, NW. 



Weather. 



Pleasant 

 Cloudy . 

 Pleasant 



Carbon 

 dioxide. 



p. ct. 

 0.028 



.030 

 .030 

 .032 

 .031 



.032 

 .030 

 .031 

 .032 

 .032 

 .032 

 .032 

 .031 



.031 

 .033 



.030 

 .029 

 .029 

 .030 

 .029 

 .027 

 .030 

 .028 

 .028 



Oxygen 



p. ct. 

 20.938 



20.941 

 20.921 

 20.933 

 20.962 



20.831 



26!942 

 20.831 

 20.932 

 20.931 

 20.923 

 20.952 



20.960 

 20.960 



20.950 

 20.961 

 20.961 

 20.951 

 20.969 

 20.960 

 20.961 

 20.964 

 20.961 



As an examination of the results showed frequent marked altera- 

 tions in oxygen content, numerous experiments were made with a view to 

 changing experimental conditions, an accurate Haldane apparatus being 

 often used. iThe variations persisted, however, and while the year's work 

 from November 3, 1909, to February 15, 1911, fully substantiated the 

 observations of earlier experimenters, by no stretch of the imagination 

 could a relationship be established between the oxygen percentages and 

 meteorological conditions, nor could any adequate explanation be found 

 as to their cause or causes. The significant fact that there was no cor- 

 responding alteration in the carbon-dioxide content this factor remain- 

 ing constant under all conditions of wind direction led us to the belief 

 that the oxygen percentage also approximated constancy, and that the 

 discrepancies appearing in the results might be attributed to errors in 

 either the technique or the apparatus. 



CONTROL ANALYSES. 



To determine the source of error it was necessary to make duplicate 

 analyses on another apparatus exactly similar in shape; consequently 

 Rudolph Grave, of Stockholm, was commissioned to construct a second 

 apparatus. In the fall of 1910 this apparatus reached Boston, but un- 

 fortunately had been utterly demolished in transit. Since it was then 

 too late in the season to secure a third apparatus for the winter's work, 

 the lack of control analyses was a very serious drawback. Finally, a cylin- 

 der of compressed air was secured from the compressed-air plant of the 

 Laboratory of Mechanical Engineering at the Massachusetts Institute of 



