40 



REPORT OF NATIONAL MUSEUM, 1884. 



March 8. 

 Oat doors rainy. Lecture began at 3.30 p. in. ; 700 persons present. 



Time. 



Dry bulb. 



Wet bulb. 



Relative humidity. 



1.00 p. m 



62° 



45 



69 



74 



58° 



44 



64 



70 



77 in laboratory. 



1.20 p. in 



2.30 p. m. 





5.00 p. m 



lecture. 

 81 lecture hall, after 





lecture. 



Carbon dioxide : 

 Mean of out-door air, 4. per 10,000. 



3 p. m., lecture ball, 9.086 per 10,000, one-balf hour before lecture. 

 4.15 p. m., lecture hall, 12.505 per 10,000, three-quarters of an hour after beginning lecture. 



Persons present declared the air to be more oppressive than on March 

 1, but the figures show no material difference.* The highest essential 

 impurity (as measured by carbon dioxide) appeared on March 6, when 

 there was no. lecture, and it is probable that if there had been a lecture 

 on that day the highest figures for contamination by respiration would 

 then have appeared. 



Summarizing the several observations, they result as follows : 



March 1. Temperature increased 4° F. during the lecture. 



March 1. Relative humidity increased 11 percent, during the lecture. 

 (Floors had been wet before lecture.) 



March 6. Temperature increased 4° during four hours in lecture hall. 



March 6. Relative humidity increased 7 per cent, during four hours. 

 (No lecture.) 



March 8. Temperature increased 5° during lecture. 



March 8. Relative humidity increased 6 per cent, during lecture. 



March 1, C0 2 exceeded outside air 3.53 per 10,000 before lecture. 



March 1, 0O 2 exceeded outside air 7.08 per 10,000 middle of lecture. 



March G, C0 2 exceeded outside air 5.44 per 10,000 at 1 p. m. (No lect- 

 ure.) 



March 8, 0O 2 exceeded outside air 5.086 per 10,000 before lecture. 



March 8, C0 2 exceeded outside air 8.505 per 10,000 near end of lecture. 



If this excess be all attributed to respiratory impurity, it has exceeded 

 "the maximum amount of respiratory impurity permissible in a prop- 

 erly ventilated space" (Dr. Chaumont), viz, 2 parts per 10,000, by — 



Parts per 10,000 before lecture March 1 1. 53 



Parts per 10,000 half through lecture March 1 5.08 



Parts per 10,000 no lecture March 6 3. 44 



Pints per 10,000 before lecture March 8 3.08fi 



Parts per 10,000 three-fourths through lecture March 8 6.505 



The increase due to respiratory impurity on the two lecture days of 

 experiment, while the lecture continued, was: 

 March 1. In half an hour, 3.55 parts per 10,000. 

 March 8. In three-fourths of an hour, 3.419 parts per 10,000. 



* In the increase of CO* during the lecture. 



