A Codd bottle is a perculiarity of the 19th century soft drinks manufacturing market, and now a sought after novelty item in the glassware collectors field.
In 1872, Hiram Codd of Suffolk, UK, patented a new design for bottles containing carbonated liquids. Codd was originally a cork manufacturer, but found the constant need to produce corks which could then not be reused a costly and wasteful venture. Instead he came up with an innovative solution utilising the glassware, which removed the need for any external seal. This design involved a small glass marble being inserted into the neck of the bottle during the manufacturing process, which could then not be removed, but which could move several centimetres up and down. The bottles were then filled with carbonated drinks such as lemonade or ginger beer and the gas within the liquid forced the glass marble upwards in the neck against an india rubber seal fixed in a groove just below the lip. To open the bottle all that was needed was for the marble to be pushed downwards, releasing the trapped gas and allowing it to fall to the bottom of the neck so the liquid could be poured out. The neck was specially designed to hold the marble in place once the pressure was released, so that it then did not obscure the mouth of the bottle should it be tilted or poured.
This particular design meant the bottles could be reused indefinitely, with a seal that would never degrade or perish. To seal the bottle after a couple of swigs, all that was needed was to hold it upside down and give it a good shake, thus returning the pressure. Before long, every soda manufacturer had caught on both in the UK and the states, but the bottles are universally known as 'Codd Bottles' after their original designer. Special Codd bottle openers were available, but inserting a little finger into the neck of the bottle also did the trick.
There were many thousands produced over a 60 year period in many different colours, some with specially coloured marbles. The cobalt blue bottle is the most sought after in the collectors market as this has a certain novelty, cobalt blue traditionally being the colour used for glassware containing poison. A Codd Bottle can be picked up quite cheaply, but this one would set you back several thousand pounds!
An unforseen consequence of the design was the prolific destruction of the bottles by children who were far more interested in the glass marbles within than the ingenious design. A sort of 19th century Kinder Surprise perhaps.
generic-man and Born2rule tell me that for those of you lucky enough to live in America or Japan, you can get your hands on modern day Codd Bottles marketed by Ramune, a Japanese soda. Or you can buy a bottle online at http://www.animenation.com/4950834100802.html.
avalyn says re Codd Bottle: A Japanese bottler called Shirakiku also makes these, in which they sell a drink called Marble Soda (which tastes much more like 7-Up than it does marbles...).
Sources:
http://www.antiquebottles.com/codd/
http://www.bottles.v-2-1.net/ - for pictures from a vast Codd Bottle collection