I saw this old Brunei stamp on ebay. Do you know what's unusual about it?
What's unusual about it is the postmark. Postmarks are usually done at the post office where the letter is posted. If it is posted in Kuala Belait, it will be postmarked Kuala Belait. Tutong etc. Notice on this stamp, it says Paquebot. But we do not have a post office with the name of Paquebot. If you can find one, let me know. I will really be surprised.
Paquebot is an interesting concept. Here is the long version of how paquebot came about. You see, in the old days, the seven oceans were not so crowded by ships as they are today. If sailing ships spotted another sail on the horizon, they usually came close, unless the crew was afraid of pirates. Especially whaling ships were happy to see company on their oftentimes two year long whaling voyages. It was the only opportunity to get some news. A long boat was lowered, captains visited each other, often dined together, and sometime even the crew was allowed to visit each other's ships and have some fun.
Of course, if one of the ships was full of oil and was heading back to it's home port, that was the only occasion to send messages back to loved ones. If the ships had the same home port, it was definitively no problem to deliver the mail. News about an arriving ship spread quickly and everyone came to check for news. But what about the ship returning to a different port, or even a different country? How was the mail delivered then? Who paid the postage and in what currency......?
Well, all of that led to an international agreement about Ship Mail known as Paquebot, French being the world's official postal language. Simply put, if you are on the open sea, which belongs to nobody, the deck you are standing on is the territory of the country under which flag the ship sails. That means, that if you write a letter on the ship's deck and on the high sea, you should be able to use the stamp of the country under which the ship sails - pirate flags excepted of course :). That also means, that if a ship enters a harbor, the officer should be able to hand over the mail to the local post office at that harbor in whatever country, and the mail should be delivered without any additional charge.
So, this Brunei stamp was carried on someone's ship in those days and the captain of the ship had the Paquebot stamp handy. The letter was stamped on board the ship and wherever the boat landed, that letter was given to the postmaster in that port and for the letter to be posted elsewhere.