PURIFICATION OF THE AIR-CURRENT WITH SODIUM BICARBONATE.
As is to be expected, the passage of so large a volume of air through the sulphuric acid in such a relatively small space results in a slight acid odor in the air-current leaving this absorber. The amount of material thus leaving the absorber is not weighable, as has been shown by repeated tests, but nevertheless there is a sufficiently irritating acid odor to make the air very uncomfortable for subsequent respiration. It has been found that this odor can be wholly eliminated by passing the air through a can containing cotton wool and dry sodium bicarbonate. This can is not weighed, and indeed, after days of use, there is no appreciable change in its weight.