Dec. 15, 1920 



Carbon-Dioxid Content of Bam Air 



407 



front of the animals. Locations 6 to 15 were in the two outer alleys and 

 therefore at the rear of the animals. Locations 1 and 6 were nearest 

 the respiration chamber. The results of the analyses are presented in 

 Table I. All samples were taken approximately 4 feet from the floor. 



Table I. — Carbon dioxid in air of barn at Durham, N. H., during January and 



February, IQIQ 



1 This position was nearest the respiration chamber. 



Since under the conditions of experimentation the amount of carbon 

 dioxid inside the respiration chamber varies from o. 1 to 0.7 per cent, 

 being usually not far from 0.35 to 0.40 per cent, and since the method of 

 experimentation depends upon the supplying of pure outdoor air with a 

 carbon-dioxid content of 0.03 per cent, it can be seen that any leakage 

 of barn air into the respiration chamber would be detrimental to the 

 success of the experiment. The fact that all the control tests of this 

 respiration chamber have shown most satisfactory agreement of results, 

 when the technic is properly carried out, testifies to the care with which 

 this chamber was constructed by the mechanician, Mr. W. E. Collins. 



