Comparative Air-Analyses 



109 



oxidation may be very irregular. The percentage of carbon dioxide is 

 slightly higher than normal, but whether this is due to oxidative processes 

 in the cylinder, to organic matter from the lubrication and rubber hose of 

 the bicycle pump, or to an actual condition of the air, the results do not show. 

 The samples collected in glass tubes were analyzed October 9 and 10, 

 1911, the results in table 67 being obtained. Although some samples 

 stored in glass have a strong tendency to decrease in the percentage of 

 carbon dioxide, these analyses show a percentage which is approximately 

 normal. With the exception of the results obtained for August 14, the 

 oxygen percentages are also normal. While apparently there is a slight 

 diminution in the percentage of oxygen, the average, 20.927 per cent, is 

 obviously affected by the results for August 14, and since at least one 

 analysis on each of the three days showed a percentage of 20.930 or over, 

 it seems hardly probable that this apparent slight decrease is significant. 



Table 67. Analyses made at the Nutrition Laboratory of air collected on summit of 



Pike's Peak 4312 meters. 



[Air collected and stored in glass samplers.] 



ANALYSES OF STREET AIR. 



While the air in the vicinity of the laboratory would be expected 

 to be somewhat contaminated with carbon dioxide and consequently 

 deficient in oxygen, it is obvious that the contaminating factors are not 

 of sufficient magnitude to affect perceptibly the analytical results. It 

 became a question of interest, however, as to how far one must go into 

 the heart of the city to secure air of less than normal oxygen content. 

 Two samples were therefore collected, in containers fitted with excellent 

 glass stop-cocks, from a crowded business street. The results of the 

 analyses are given in table 68. 



The percentage of oxygen was slightly, though almost imperceptibly, 

 less than that in normal air, while the carbon dioxide was slightly higher 

 than the average normal. Since by reference to table 61 it can be seen 

 that the samples analyzed at the laboratory on the same date showed 

 20.939 per cent of oxygen and 0.029 per cent of carbon dioxide, it can be 



