OCR Text |
Show Air Necessary for Hurrun Utfat Every time we breathe, we draw thirty cublo Inches of air into oar lungs; supposing that we take fifteen breaths a minute for the twenty-four hours of the day, we use no less than 643,000 cubic inches of air, which would weigh over thirty pounds. One day's supply of air for one human being would be sufficient to fill 1,125 two-gallou cans ; a year's supply would weigh more than five tons. From these- figures It may be seen how necessary It is to keep windows open so that there may be a continuous continu-ous supply of fresh air. |