They were thirsty too, for they had none too much water, and in all the time they had seen neither spring nor stream. This was their state when one day they found their path blocked by a running water. It flowed fast and strong but not very wide right across the way, and it was black, or looked it in the gloom. It was well that Beorn had warned them against it, or they would have drunk from it, whatever its colour, and filled some of their emptied skins at its bank. As it was they only thought of how to cross it without wetting themselves in its water. There had been a bridge of wood across, but it had rotted and fallen leaving only the broken posts near the bank.

Bilbo kneeling on the brink and peering forward cried: “There is a boat against the far bank! Now why couldn’t it have been this side!”
“How far away do you think it is?” asked Thorin, for by now they knew Bilbo had the sharpest eyes among them.
“Not at all far. I shouldn’t think above twelve yards.”
“Twelve yards! I should have thought it was thirty at least, but my eyes don’t see as well as they used a hundred years ago.

Chapter 8 Flies and Spiders