The other day I was asked what a blog was. Of course most folks know it is short for Web-Log. I explained that a log was a sort of diary or journal to record things in. The captains on ships keep Logs.
Wouldn't you know it, in this day and age, I actually went to the bookshelf and pulled out an encycolpedia "L" book. I am told very few people do that anymore! It is sometimes faster than "firing up" the computer. What I found there was very interesting.
The Ship's Log was actually a record of the ship's log. There was a piece of wood, called a chip log, that they would throw over the back of the ship in the olden days.
The log was connected to the ship by a rope, and that rope had knots tied in it at intervals (that is where the nautical speed measurment "knots" comes from).
The rope with the knots was attatched to a reel on the ship, and however many "knots" were unreeled indicated how fast the ship was going.
That speed, along with the wind direction and other weather and sea observations, was recorded in the book of the ships' log. The Captain would often record other things that happened, battles, births, deaths, sightings of other ships, etc.