Gehler’s Physikalisches Wörterbuch, consisting of six parts including a supplement and an index volume, was published between 1787 and 1796. It is a reliable reference book for experimental physics, applied mathematics and chemistry at the end of the eighteenth century. Fischer’s Physikalisches Wörterbuch appeared a few years later. The principal difference to Gehler’s dictionary is its philosophical foundation. Under the influence of Kant’s and Schelling’s philosophy of nature, Fischer intends to demonstrate the superiority of a so-called dynamic explanation of natural phenomena ("dynamische Lehrart der Physik"). This dictionary of five original volumes, a supplementary volume, an index volume and three more volumes without index is very difficult to handle, and after 1825, it was overshadowed by the striking success of a revised and enlarged edition of Gehler’s Physikalisches Wörterbuch, published by a group of physicists who were strongly opposed to Naturphilosophie.