Consisting of a series of case studies, this book is devoted to the concept and uses of salt in early modern science, which have played a crucial role in the evolution of matter theory from Aristotelian concepts of the elements to Newtonian chymistry. No reliable study on this subject has been previously available. Its exploration of natural history’s and medicine’s intersection with chemical investigation in early modern England demonstrates the growing importance of the senses and experience as causes of intellectual change from 1650-1750. It demonstrates that an understanding of the changing definitions of “salt” is also crucial to a historical comprehension of the transition between alchemy and chemistry.