CONTAMINATED AIR 



161 



respirator consists of a canvas cup carrying a wet sponge or 

 cloth (see Fig. 54) through which the breathed air must pass, 

 leaving the dust behind. The gas masks worn by our soldiers 

 in France and by firemen serve a similar purpose. 



Dust is constantly being produced in the home, on the 

 street, in the school, etc. This dust settles on the floor, on the 



FIG. 54. Respirator 



In many industrial processes it is impracticable to remove the dust by mechanical 



means. The respirator is worn by the worker to filter the dust out of the air which he 



breathes. The sectional view shows the valve, z>, and the sponge, s, through which the 



air is filtered. (From photograph lent by the American Museum of Safety) 



furniture, and on the books and utensils. Careless housekeepers 

 or janitors sometimes try to produce the appearance of clean- 

 liness by removing the dust in the quickest way, that is, by 

 throwing it into the air, where it cannot be so easily noticed. 

 From the point of view of people's health, this is a foolish 

 way of keeping clean. Within the last few years feather dusters 

 have gone quite out of fashion, and in some places their 



