THE MICROBIOLOGY OF THE ATMOSPHERE 



century. Largely through the influence of the chemist, J. B. A. Dumas, the 

 Observatoire Montsouris was launched as a State institution in 1871 to 

 make records needed for meteorology and agriculture. The Observatoire 

 was housed in a palace in the Pare Montsouris, about 5 km. south of 

 the centre of Paris. One of its tasks was to be the microscopic and cul- 

 tural study of the organic and inorganic dust in the air, including both 

 Mucedineae (moulds) and bacteria. 



B A 



Fig. 2. — Cunningham's aeroconiscope. A = side view of apparatus 

 (partly in section) ; B = face view of sticky surface behind apex of cone 

 (on a larger scale). 



Observations were started in 1875 by M. Schoenauer. He was re- 

 placed after a year or two by Pierre Miquel {b. 1850, d. 1922), the dis- 

 tinguished bacteriologist, who continued in charge of the work for over a 

 quarter of a century. During the course of the survey, various methods 

 were tested and discarded or improved; but all aimed at estimating the 



