'O,' it appears, is the French for hot-water.

The Colonel (though he despises it heartily) thinks he speaks the language remarkably well.

Whilst he was inhausting his smoking tea, which went rolling and gurgling down his throat, and hissing over the 'hot coppers' of that respectable veteran, a friend joined him, with a wizened face and very black wig, evidently a Colonel too.
The two warriors, waggling their old heads at each other, presently joined breakfast, and fell into conversation, and we had the advantage of hearing about the old war, and some pleasant conjectures as to the next, which they considered imminent.

They psha'd the French fleet; they pooh-pooh'd the French commercial marine; they showed how, in a war, there would be a cordon ('a cordong, by---') of steamers along our coast, and 'by -- -,' ready at a minute to land anywhere on the other shore, to give the French as good a thrashing as they got in the last war, 'by -- -'.

In fact, a rumbling cannonade of oaths was fired by the two veterans during the whole of their conversation.
There was a Frenchman in the room, but as he had not been above ten years in London, of course he did not speak the language, and lost the benefit of the conversation.