Sea-water chemistry has intrigued a variety of scholars for a variety of reasons. Dominant is a great curiosity to understand the nature of our surroundings—a quest that has involved the earliest philosophers to twentieth-century scientists such as those who penetrate the great depths of the oceans in such an artificial exo-skeleton as the bathyscaphe. The exploitations of both the living and mineral resources of the sea have motivated many investigations. The rising food demands for an increasing world population have resulted in extensive searches for the factors governing biological productivity, including the chemical species related to the photosynthetic activities of marine plants. Systematic marine mineral explorations utilise the results of investigations upon the chemical factors that govern precipitation processes in sea water and upon the chemical make-up of rivers. More recently, the remarkable abilities of human society to alter the compositions of the waters and airs of the environment have necessitated an immediate expansion in our knowledge of oceanic chemistries in order to predict the responses of the marine environment, including its inhabitants, to such incursions. By such stimuli the moods of marine chemistry have been fashioned over the past two centuries.