The flag of the United States shall be thirteen horizontal stripes, alternate red and white; and the union of the flag shall be forty-eight [now - fifty] stars, white in a blue field. On the admission of a new State into the Union one star shall be added to the union of the flag; and such addition shall take effect on the fourth day of July then next succeeding such admission.
(US Code, Title 4, Chapter 1, The Flag)