Period 1 element (He) is a colorless, odorless, tasteless, non-toxic, inert monatomic chemical element that heads the noble gas series in the periodic table and whose atomic number is 2. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions. Helium was discovered in 1868 by French astronomer Pierre Janssen, who first detected the substance as an unknown yellow spectral line signature in light from a solar eclipse. In 1903, large reserves of helium were found in the natural gas fields of the United States, which is by far the largest
Lowest bridging point often was at a location that allowed seagoing traffic to approach it from a downstream direction. Examples of lowest bridging points in Britain include London, the lowest bridging point on the Thames; Lancaster, the lowest bridging point on the Lune; York, the lowest bridging point on the Ouse; and Gloucester, the lowest bridging point on the Severn. Glasgow grew up at the lowest bridging point on the Clyde which was about twelve miles upstream from its lowest fording point at Dumbuck. Mathew Paris’s map of 1247 appears to show only one bridge in the whole of Britain: at Stirling, the