Bottled water is drinking water (e.g., well water, distilled water, mineral water, or spring water) packaged in plastic or glass water bottles. Bottled water may be carbonated or not. Sizes range from small single serving bottles to large carboys for water coolers. Although vessels to bottle and transport water were part of the earliest human civilizations, bottling water began in the United Kingdom with the first water bottling at the Holy Well in 1621. The demand for bottled water was fueled in large part by the resurgence in spa-going and water therapy among Europeans and American colonists in the 17th and 18th centuries. The first commercially distributed water in America was bottled and sold by Jackson's Spa in Boston in 1767. Early drinkers of bottled spa waters believed that the water at these mineral springs had therapeutic properties and that bathing in or drinking the water could help treat many common ailments. The popularity of bottled mineral waters quickly led to a market for imitation products. Carbonated waters developed as means for approximating the natural effervescence of spring-bottled water, and in 1809 Joseph Hawkins was issued the first U.S. patent for “imitation” mineral water. As technological innovation in nineteenth century lowered the cost of making glass and improved production speed for bottling, bottled water was able to be produced on a larger scale and the beverage grew in popularity. Bottled water was seen by many as a safer alternative to 19th century municipal water supplies that could be contaminated with pathogens such as cholera and typhoid. By the middle of the century one of America's most popular bottlers, Saratoga Springs, was producing more than 7 million bottles of water annually. In the United States, the popularity of bottled water declined in the early 20th century, when the advent of water chlorination reduced public concerns about water-borne diseases in municipal water supplies. However, it remained popular in Europe, where it spread to cafes and grocery stores in the second half of the century. Perrier water had been bottled since the 19th century and widely sold throughout the British Empire; in 1977 Perrier launched in the United States. Today, bottled water is the second most popular commercial beverage in the United States, with about half the domestic consumption as soft drinks. Many of the early developments in the field of chemistry can be attributed to the study of natural mineral waters and attempts to replicate them for commercial sale. Joseph Priestley, who would discover oxygen in 1775, made his first contributions to the field of chemistry by dissolving carbon dioxide in water, for which he was awarded the Copley Medal in 1773. He would go on to work with Johann Jacob Schweppe, founder of Schweppes, in developing “aerated” waters for commercial sale. In 1973, DuPont engineer Nathaniel Wyeth patented Polyethylene terephthalate (PET) bottles, the first plastic bottle to be able to withstand the pressure of carbonated liquids. Today, PET plastic has replaced glass as the preferred material for single-serving bottled water containers due to its light weight and resistance to breaking. In 2015, the plastic that water bottles are made out of was changed to be thinner due to government regulations. Some of the more common types of bottled water are: