In it the author described the use of a car tube as an emergencey air supply. The tube was inflated and just prior to connecting to a suitable air line, the valve was loosened slightly to allow the right volume of air to escape.
Imagine the possibilities for those that suffer from frequent power failures! You could purchase a tractor tube, connect it up and "hey presto", air supply for days on end. If you inflate the tube at your local garage you could save on power costs by not running an electric pump and by placing it in front of your aquarium you could use it as a comfortable lounge chair!
The only downfall would be the looks you would get from people as you walked home from the garage with a huge inflated tractor tube.