Observe the rule, never to approach a supposed leakage with a light. Fortunately the gas, which threatens our lives, warns us of the danger by its pungent smell. The first thing to be done is to open windows and doors, and to ventilate the apartment. Then turn the gas off at the main, and wait a short time until the accumulated gas has been dispersed.
66. Does hydrogen gas rise or fall when it escapes?
Being twelve times lighter than common air it rises, and therefore it would be better for ventilation to open the window at the top than at the bottom. But all gases exhibit a strong tendency to diffuse themselves, and therefore they do not rise or fall in the degree that might be anticipated.
67. What proportion of hydrogen in the air is dangerous to life, if inhaled?
One-fiftieth part has been found to have a serious effect upon animals. The effects it produces upon the human system are those of depression, headache, sickness, and general prostration of the vital powers. It is therefore advisable to observe precautions in the use of gas.
"From the place of his habitation he looketh upon all the inhabitants of the earth."—Psalm xxxiii.
68. What proportion of gas in the air may be recognised by the smell?