Beginning of Essay
Helium was discovered by a French astronomer named Pierre-Julius-Cesar Janssen. The French astronomer got evidence for the element during solar eclipse in 1868. He detected new lines in the solar spectrum. Later in 1895 Sir William Ramsay discovered it in cl ....

Middle of Essay
.... of gases in the normal breathing process, the blood stream absorbs oxygen from air in the lungs, while carbon dioxide passes from the blood to the air. When you hold your breath, the exchange of gases slows, as "stale" air in the lungs is no longer replaced by "fresh" air. Oxygen is actually removed from the blood stream during the exchange of gases. depending on how completely oxygen is replaced by helium, you may lose consciousness quickly and without warning - you may literally pass out while still standing. The usual result is an uncontrolled fall that can cause serious injury, even if normal breathing resumes before brain damage occurs du ....