Apparatus and Methods 81 



in 15 c. c. of distilled water. By means of the funnel and tube, the mixed 

 solutions were then carefully introduced into chamber D. One such charge 

 of potassium pyrogallate was found to be sufficient to make approximately 

 30 air-analyses. 



This solution takes up oxygen rapidly and has a high absorptive ca- 

 pacity. It has been assumed that since the solution was so much more 

 concentrated than Hempel's, his assertion that no carbon monoxide was 

 developed with his weaker solutions held true in this case also, particu- 

 larly as Haldane states that with his extremely concentrated solution no 

 traces of carbon monoxide are found. Furthermore, certain evidence 

 here presented seems to support this view. When a known sample of air 

 is analyzed a number of times, the percentage of oxygen at the beginning 

 of the series does not differ from that found at the end, even when as many 

 as 30 analyses are made with the one charge of potassium pyrogallate. 

 It seems reasonable to suppose that if carbon monoxide were formed, a 

 somewhat different amount would be produced after the first, second, or 

 third analysis than after the twenty-eighth or twenty-ninth. On the 

 other hand, it is not impossible that in the production of carbon monoxide 

 there may be an extremely small quantitative relationship between the 

 oxygen absorbed and the disintegration of the pyrogallic acid, so that 

 the carbon monoxide given off may remain strictly proportional to the 

 amount of oxygen consumed. Since in each of these analyses exactly the 

 same amount of oxygen is absorbed, there still may be a slight constant 

 factor present; consequently, it is necessary to take into consideration the 

 fact that in all of these analyses there may be traces of carbon monoxide 

 produced. In that case the tendency would be to make the percentage 

 of oxygen slightly too small. Although throughout the whole research 

 a slightly modified Haldane solution was used, subsequent experiments 

 with the Haldane formula show a somewhat larger oxygen percentage. 

 This increased percentage may be due to two causes: (1) the actual ab- 

 sorption of more oxygen, or what is more probable, (2) the formation of 

 less or no carbon monoxide. It remains a fact, nevertheless, that the 

 solution as used is without question suitable for a comparative study of 

 the oxygen percentage of the atmosphere. 



