Sometimes it is possible that the emotions that you experience when riding in a gondola makes you forget some personal item such as a camera, a pair of glasses, your diary or other item behind.
Even if the gondolier looks after the items that you have forgotten in his boat, there is no way that he would ever be able to find you to give them to you again, because obviously he does not know you nor where you are staying.
The only way in which you can trace the gondola which you have hired and therefore recover what you have left behind, is to remember the licence number of the boat. Each gondola has a number that is carved onto a metal plate and screwed onto the side of the boat.