86 POPULAR SCIENCE MONTHLY. 



When, a year ago, the wi-iter, in a paper on Theater Sanitation' 

 presented at the annual meeting of the American Public Health 

 Association, stated that " chemical analyses show the air in the 

 dress circle and gallery of many a theater to be in the evening 

 more foul than the air of street sewers," the statement was re- 

 ceived by some of his critics with incredulity. Yet the fact is true 

 of many theaters. Taking the amount of carbonic acid in the air 

 as an indication of its contamination, and assuming that the or- 

 ganic vapors are in proportion to the amount of carbonic acid (not 

 including the CO2 due to the products of illumination), we know 

 that normal outdoor air contains from 0.03 to 0.04 parts of CO2 

 per 100 parts of air, while a few chemical analyses of the air in 

 English theaters, quoted below, suffice to prove how large the con- 

 tamination sometimes is: 



Strand Theater, 10 p. m., gallery 0. 101 parts COj per 100. 



Surrey Theater, 10 p. M., boxes 0.111 " " " 



Surrey Theater, 12 p. M., boxes 0.218 " " " 



Olympia Theater, 11.30 p M., boxes 0.082 " " " 



Olympla Theater, 11.55 P.M., boxes 0.101 " " " 



Victoria Theater, 10 P.M., boxes 0.126 " " " 



Haymarket Theater, 11. .30 p. M., dress circle 0.076 " " " 



City of London Theater, 11.15 P.M., pit 0.252 " " " 



Standard Theater, 11 p. M., pit 0.320 " " " 



Theater Royal, Manchester, pit 0.2734 " " " 



Grand Theater, Leeds, pit 0.150 " " " 



Grand Theater, Leeds, upper circle 0.143 " " " 



Grand Theater, balcony 0.142 " " " 



Prince's Theater, Manchester 0.11-0.17 " " " 



(Analyses made by Drs. Smith, Bernays, and De Chaumont.) 



Compare with these figures some analyses of the air of sewers. 

 Dr. Russell, of Glasgow, found the air of a well-ventilated and 

 flushed sewer to cont.iin 0.051 vols, of COg. The late Prof. "W. 

 Ripley ^Nichols conducted many careful experiments on the 

 amount of carbonic acid in the Boston sewers, and found the fol- 

 lowing averages, viz., 0.087, 0.082, 0.115, 0.107, 0,08, or much 

 less than the above analyses of theater air showed. He states: 

 " It appears from these examinations that the air even in a tide- 

 locked sewer does not differ from the standard as much as many 

 no doubt suppose." 



A comparison of the number of bacteria found in a cubic foot 

 of air inside of a theater and in the street air would form a more 

 convincing statement, but I have been unable to find published 

 records of any such bacteriological tests. Nevertheless, we know 

 that while the atmosphere contains some bacteria, the indoor air 

 of crowded assembly halls, laden with floating dust, is particularly 



