The concept of the prime meridian was adopted by the first district in Algeria. When the Americas were discovered, the West chose to make the people of each country establish their prime meridian in their own land. They attributed everything else to it, as the French did. They made their prime meridian in the city of Paris, and some scholars among them continued to take longitudes from the island of Al-Hayd in Algeria. In reality, it appears that a common meridian was adopted as a principle by the nations, to which everything else was attributed. It would be in a country with no inhabitants after it, or a distinguished place like Mecca. Then, the method of determining longitude, as it was taken there, was based on the difference in times. It is known that the sun, or the Earth as the Europeans say, completes its daily motion in twenty-four hours. It traverses fifteen degrees of the circle it draws in its path every hour, meaning it traverses one degree every four minutes. This means that if noon arrives in Cairo, for example, it will not arrive in a place fifteen degrees west of it except after an hour, and it will arrive after two hours in a place thirty degrees away, and so on. The opposite is true for a place to the east. If it is noon in Cairo, an hour after noon will have passed in a place fifteen degrees east of it, and two hours will have passed in a place thirty degrees away, and so forth. Here, it is denied that if it is noon in the western parts of the West and its eastern parts, how can it be in them? Thus, their distance from these countries is understood. It is said that if it is noon in Cairo, Egypt, it will not be noon in Paris until two hours and four minutes have passed. And if it is noon in Istanbul, it was noon in Paris after the passage of