In 1857, Llewellyn Jewitt became secretary and the museum was opened to the general public on Saturday mornings. In 1858 the Derby Philosophical Society moved to a house on the Wardwick in Derby as it merged with what was called the Derby Town and County Museum and the Natural History Society. This move included the society's library of 4,000 volumes, mathematical and scientific apparatus and its collection of fossils. In 1863 the botanist Alexander Croall was appointed the first Librarian and Curator and the following year the museum and library were joined together. Croall left in 1875 to become the curator of the Smith Institute in Stirling.