Sailing boats

To prevent a boat from tipping in strong winds, a ballast is often placed in the keel. Lead is commonly used for a ballast because of its high density and resistance against corrosion.

Glass fibres are used in some boats for reinforcement purposes. Large furnaces are needed for the manufacture of glass fibres to successfully and gradually melt the silica sand, limestone, kaolin clay, fluorspar, colemanite, dolomite and other minerals to liquid form.

Stone houses

‘Trim’ houses on the Island of Hvar were the first buildings of the Stone Age and today

many of them still stand with the original foundations. Some of the houses were built without any mortar between the thick walls which allowed for pleasant temperatures both in the summer and winter.