These large bottles are known as demijohns or carboys. They were used, quite simply for holding bulk quantities of liquids of all kinds - mineral water, acids, vinegar, chemicals, etc. Prior to the days of plastic, metal and wood were commonly used. Glass offers an alternative which does not react/break down when in contact with the contents.
Earlier freeblown examples are very collectible and some can be quite valuable. The visual appeal of the shape and the color play a big role in value.
The aqua examples pictured above are plain but still have some value.
Chris