The Master's Hat
We know that the Master's Hat is worn in every meeting by the WM, but what significance does it have?
Why is it that the Master wears a hat? It is said that being "covered" has a meaning of authority. For one, it is human nature to first look someone in the eye, and hence the item worn upon one's head is one of the first things people see. The fact that one is wearing anything on ones head, was from ancient times seen as a point differentiating that person somehow. Some decorations were added to make objects such as crowns and wreathes which are a visual reminders of certain authority and particular rank...
To the Romans, hats was a sign of fret "every man praying or prophesying, having the head covered, doth dishonors his head..." In other words one dishonors God by praying while "covered". It is for this reason that the Master removes his hat while praying. Dom, which was especially worn after the death of the dreaded Emperor Nero, and it was therefore that in the past all Masons attending Lodge wore hats, as a symbol of that freedom and brotherly equality (which is still done in Danish Freemasonry). The head is also widely seen as a direct link to God by many beliefs. For example Corinthian 11:3 it mentions "......and I wish you to know that of every man the head is the Christ....".
In French Masonry a new Master of a Lodge receives a hat with the words "with this hat you may cover yourself in the future," again pointing to a certain authority bestowed upon the Master of the Lodge. It is also interesting to note that in the old days the speaker of the British House of Commons had to wear a hat.