Born and bred in the city, as a child I was always fascinated by these Soda bottles when ever we went to the countryside down south. When I saw these bottles, my first reaction was “how did they put the marble inside?”
Who ever designed it in the first place must have done a lot of thinking. For example, after you open the bottle, it has to be tilted to pour it into a glass(or drink directly) and in the process the marble rolls back to the neck thereby stopping the flow. So a notch was provided inside the bottle (little away from the neck) and you hold the bottle in such a way that the marble gets lodged in that notch when tilted.
A tiny washer is also lodged inside the bottle for perfect sealing (glass to glass contact will not seal)
These bottles are still seen in some shops in Goa and the coastal parts of Kerala. My daughter got me two, the one which is standing is filled and the other is empty. (wonder if there is any expiry time limit for the filled one)
As a kid we all have played with marbles, different colors and sizes, but I always wondered why they used only dark blue marbles in these bottles ?