Anhydrous or Calcium Chloride Fused is very hygroscopic, meaning it rapidly absorbs moisture. It is also deliquescent, thus it is employed as a drying agent in a desiccator. Because concentrated sulphuric acid is hygroscopic, it takes moisture from the air and dilutes it, acting as a drying and dehydrating agent and therefore being employed in a desiccator. Fused relates to the fact that this porous mass has been granulated but not scattered in order to enhance the surface area and enhance its dehumidifying capabilities.