That year, the United States was divided into four time zones roughly centered on the 75th, 90th, 105th, and 120th meridians. At noon, on November 18, 1883, telegraph lines transmitted GMT time to major cities where authorities adjusted their clocks to their zone’s proper time. On November 1, 1884, the International Meridian Conference in Washington, D. C., applied the same procedure to zones all around the world. The 24 standard meridians, every 15 east and west of 0 at Greenwich, England, were designated the centers of the zones. The international dateline was drawn to generally follow the 180 meridian in the Pacific Ocean. Because some countries, islands and states do not want to be divided into several zones, the zones’ boundaries tend to wander considerably from straight north-south lines.
