A history of the scientific investigation of limestone caves, to 1900.

This thesis is primarily concerned with geomorphological aspects of caves - karst hydrology, speleogenesis and the origin of speleothems. Cave exploration was a necessaiy prerequisite for such studies and its progress is traced from prehistoric times to the systematic regional investigations of the 17th century and later, The first extensive work was in Slovenia, stimulated by the practical importance there of karst hydrology for water supply and flood control. Large karst springs had long attracted attention and several hypotheses had been advanced previously; according to some they were supplied by water raised from the sea, others explained them by condensation and finally their source as rainfall was accepted. The study of intermittent karst lakes led eventually to the postulation of what amounted to a water-table. A true understanding of speleogenesis and the origin of speleothems depended on a knowledge of the chemistry of limestone solution, which in its turn depended on the rejection of phlogiston at the end of the 18th century. Before that time only mechanical erosion was normally conceived as a means of removing particles of solid rock and subsequently redepositig them to form speleothems although a few people earlier in the century had involved an unspecified "aerial acid". There were also several more primitive theories including the formation of caves by tectonic "catastrophes", by erosion as the water of Noah's Flood drained back underground, and the inflation of cavities in still soft limestone by decomposition gases. For many years speleothems were thought to possess a low form of life, growing like plants rather than by accretion. After the action of carbon dioxide in speleogenesis was appreciated a new question arose - whether caves could be formed in the saturated zone or whether they were due solely to vadose water. For many years the problem was not recognized but violent controversy was taking place over it by the end of the 19th century.