Here's a bit of trivia which may interest you transatlantic gentlemen.
In the British Army and the RAF, soldiers and airmen salute with the palm of the hand facing forwards. In the Royal Navy, sailors salute with the palm facing downwards. All members of the American armed forces salute with the palm facing downwards.
In the 1989 film "Glory," a film about the 54th Massachusetts Infantry Regiment, part of the Union Army, which was made up of black soldiers under the command of a white colonel, there is a scene in which there is an altercation between a white corporal and a black sergeant played by Morgan Freeman. This altercation is broken up by an officer who rides up on a horse. Both soldiers salute the officer who returns the salute but they all salute with the palm of the hand facing forwards, British style.
Is this how the Union Army saluted during the Civil War or is this just sloppy directing? If this is historically correct, when did the American armed services adopt the palm downwards salute?