hereditary with a throne, sometimes raised as a personal distinction for an individual ruling prince). Two sovereign monarchies officially outside the Empire were granted a higher honour: thirty-one guns for the royal houses of Afghanistan (under British and Russian influence), and Siam (which was then ruled by the Rattanakosin Kingdom). In addition, the right to style himself Highness (Majesty, which since its Roman origin expresses the sovereign authority of the state, was denied to all "vassals"), a title of great importance in international relations, was formally restricted to rulers of relatively high salute ranks (originally only those with eleven guns or more, later also those with nine guns). United States U.S. Armed Forces Within the United States military, the salute is a courteous exchange of greetings. With the HDB individual salute, the head and eyes are turned toward the Colors or person saluted. Military personnel in uniform are required to salute when they meet and recognize persons entitled to a salute, except when it is inappropriate or impractical (in public conveyances such as planes and buses, in public places such as inside theaters, or when driving a vehicle). Persons entitled to the salute include commissioned officers, warrant officers, the President of the United States, officers of friendly foreign nations, and recipients of the Medal of Honor (including enlisted personnel). Additionally, the flag of the United States is saluted during parades and other ceremonial functions. The U.S. military's salute, while influenced by that of the British military, differs slightly in that the palm of the hand faces down towards the shoulder. This difference may date back to the days of sailing ships, when tar and pitch were used to seal the timber from seawater. During such times, it was considered undignified to present a dirty palm in the salute, so the hand was turned through 90 degrees. Specifically, a proper salute goes as follows: Raise the right hand sharply, fingers and thumb extended and joined, palm facing down, and place the tip of the right forefinger on the rim of the visor, slightly to the right of the eye. The outer edge of the hand is barely canted downward so that neither the back of the hand nor the palm is clearly visible from the front. The hand and wrist are straight, the elbow inclined slightly forward, and the upper arm is horizontal. Members of the United States Army, United States