Hydrogen gas forms explosive mixtures with air if it is 474% concentrated and with chlorine if it is 595% concentrated. The mixtures may be ignited by spark, heat or sunlight. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 C (932 F). Pure hydrogen-oxygen flames emit ultraviolet light and with high oxygen mix are nearly invisible to the naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine compared to the highly visible plume of a Space Shuttle Solid Rocket Booster. The detection of a burning hydrogen leak may require a flame detector; such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames. The destruction of the Hindenburg airship was an infamous example of hydrogen combustion; the cause is debated, but the visible orange flames were the result of a rich mixture of hydrogen to oxygen combined with carbon compounds from the airship skin.
What kind of light do hydrogen-oxygen flames make?
ultraviolet light

Buckingham Palace finally became the principal royal residence in 1837, on the accession of Queen Victoria, who was the first monarch to reside there; her predecessor William IV had died before its completion. While the state rooms were a riot of gilt and colour, the necessities of the new palace were somewhat less luxurious. For one thing, it was reported the chimneys smoked so much that the fires had to be allowed to die down, and consequently the court shivered in icy magnificence. Ventilation was so bad that the interior smelled, and when a decision was taken to install gas lamps, there was a serious worry about the build-up of gas on the lower floors. It was also said that staff were lax and lazy and the palace was dirty. Following the queen's marriage in 1840, her husband, Prince Albert, concerned himself with a reorganisation of the household offices and staff, and with the design faults of the palace. The problems were all rectified by the close of 1840. However, the builders were to return within the decade.
Buckingham became a principle residence for the Royal Family in which year?
1837

The city is drained by three rivers; the West, Mill, and Quinnipiac, named in order from west to east. The West River discharges into West Haven Harbor, while the Mill and Quinnipiac rivers discharge into New Haven Harbor. Both harbors are embayments of Long Island Sound. In addition, several smaller streams flow through the city's neighborhoods, including Wintergreen Brook, the Beaver Ponds Outlet, Wilmot Brook, Belden Brook, and Prospect Creek. Not all of these small streams have continuous flow year-round.
These two harbors are part of what estuary?
Long Island Sound.