. Elementary biology; an introduction to the science of life . 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, b
. Elementary biology; an introduction to the science of life . 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
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Keywords: ., bookcentury1900, bookdecade1920, bookpublishe, booksubjectbiology
