One of these records was a true one; this he kept for himself.

The other was a false one; this he kept to show his sailors.

So while they thought they were sailing slowly and that the ocean was not so very wide, Columbus knew from his own true record that they were getting miles and miles away from home.
Soon another thing happened to worry the sailors.

The pilots were steering by the compass.

You know what that is--a sort of big magnet-needle perfectly balanced and pointing always to the north.