The law makes no special mandate. In 1789, Justice James Wilson was sworn in by the mayor of Philadelphia, Pennsylvania, where the court first sat. Thurgood Marshall, the nation's first African-American justice, took the Constitutional Oath in 1967 from Associate Justice Hugo Black, an Alabaman.
ballast - A device required by electric-discharge light sources such as fluorescent or HID lamps to regulate voltage and current supplied to the lamp during start and throughout operation.
Ballast Factor (BF) is a measurement that compares the ratio of light output of a lamp or lamps operated by a specific ballast to the light output of the same lamp or lamps operated by a standard reference ballast. The higher the BF is, the higher the wattage running through the ballast.