RESUMO
This article considers how chemical analyses were employed not only to study and describe mineral waters, but also to promote new spas, and to reinforce the scientific authority of experts. Scientists, jointly with bath owners, visitors and local authorities, created a significant spa market by transforming rural spaces into social and economic sites. The paper analyses the role developed by the chemist Antonio Casares in the commodification of mineral water in mid-19(th) century Spain. His scientific publications and water analyses put a new economic value on some Spanish mineral waters and rural springs. First the paper explores the relationship between geographic factors, regulation, and spa development in 19(th) century Spain, and considers how scientific work improved the economy of some rural areas. Then the transformation of numerous country springs into spas, and the commodification of baths as places between science and leisure is examined. Finally the location of spas across the borders of medicine and chemistry is shown, together with the complex field operations required to study mineral waters. This paper reveals an intense circulation of knowledge between the field, laboratories and scientific publications, as well as the essential role developed by experts like Casares, who not only contributed to the study of rural springs but also to their economic transformation.