A Discourse of Bathe, and the hot waters there; frontispiece, 1676. Several vignettes: sun symbols above and below a view of Bathe (in oval); to the left stands an apothecary, to the right a palm tree; and directly below the oval of Bathe stands a man with a walking stick. Balneology is the branch of medical science concerned with the therapeutic value of baths, especially those taken with natural mineral waters. Balneotherapy may involve hot or cold water, massage through moving water, relaxation or stimulation. Many mineral waters at spas are rich in particular minerals (silica, sulfur, selenium, radium) which can be absorbed through the skin.