26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



the oxygen and aqueous vapor of the air, is converted into sulphuric 

 acid.' 



The presence of sulphur in coal, or in iron pyrites contained in 

 coal, is responsible for this acid product and Prof. Schaefer believes 

 that sulphur dioxide, being a very heavy gas, with a specific gravity 

 of 2.25, is alone capable of creating a fog, or is at once shown when 

 it is brought- in contact with the atmosphere, from which it absorbs 

 aqueous vapor, causing dense, heavy fumes. The dust or carbon 

 particles, coming in contact with this acid vapor, enhance its grav- 

 ity materially. 



Prof. Baskerville some time ago made a number of determinations 

 of the sulphur dioxide content of the air of New York city. Stations 

 were established throughout greater New York city, including high 

 ofifice buildings, parks, subways, stations, and railroad tunnels ; and 

 very variable results, as might be expected, were obtained. The 

 determinations may, in part, be thus summarized : 



Locality SO2 in parts in a million 



Elevated portion of city, near a 



high stack 3.14 



Various parks 0.84 (maximum; others negative) 



Railroad tunnels 8.54 — 31.50 



Subway None 



Downtown region 1.05 — 5.60 



Localities near a railroad 1.12 — 8.40 



In 1907, the residents of Stat en Island, as well as some on Long- 

 Island, complained of the noxious nature of the air wafted over from 

 various plants in New Jersey. This induced the Department of 

 Health of the City of New York to investigate the air and vegetation 

 in the vicinity of the Borough of Richmond, Staten Island, and 

 some of the results obtained are given below by permission of the 

 Department. 



Substance Impurity 



Air Trace of sulphuric acid 



Air 0.0066 per cent. SO2 by weight 



Air Trace of sulphuric acid 



Grass (three samples) Sulphuric acid present 



Grass 0.24 per cent SO3 



Grass 0.70 per cent SO3 



Leaves ' 0.19 per cent SO3 



Leaves 028 per cent SO3 



Soil 0.0015 per cent SO3 



^ Theodore W. Schaefer : The Contamination of the Air of our Cities with 

 Sulphur Dioxide, the Cause of Respiratory Disease. Boston Medical and 

 Surgical Journal, July 25, 1907. 



