Experimental History of the Materia Medica, London, 1761 Digital edition by the University and State Library Dusseldorf; 3rd edit, by J. Aiken, 1784; German translation,1771.
Willhelm Lewis Materia medica oder Beschreibung der einfachen Arzneymittel . Orell, Gesner, Fueslin & Co., Zurich 1771 Digital edition by the University and State Library Dusseldorf
Commercium Philosophico-Technicum, London, 1763 Digital edition, 4to.
Neues verbessertes Dispensatorium oder Arzneybuch, in welchem alles, was zu der Apothekerkunst gehoret, nach den Londoner und Edinburger Pharmacopeen mit practischen Wahrnehmungen und Bemerkungen vorgetragen wird ; aus dem Englandischen ubersetzet. Brandt, Hamburg 2 Bande 1768/1772 Digital edition by the University and State Library Dusseldorf
The new dispensatory : containing 1. The elements of pharmacy, 2. The materia medica, or an account of the substances employed in medicine, 3. The preparations and compositions of the new London and Edinburgh pharmacopoeias ; the whole interspersed with practical cautions and observations. F. Wingrave, London 6th ed. 1799 Digital edition by the University and State Library Dusseldorf
Lewis also published translations of Caspar Neumann's chemical works in 1759 Digital edition and 1773 (Vol. I & Vol. II), and (posthumously) of Hoffman's System of the Practice of Medicine (1783).
In 1754 and 1757 he published a series of original papers on platinum: Phil. Trans. R. Soc. 48 (1754) 638?689 (Papers I-IV), Phil. Trans. R. Soc. 50 (1757) 148?155 (Paper V) & Phil. Trans. R. Soc. 50 (1757) 156?166 (Paper VI). In 1767 the Society for the Improvement of Arts, Manufactures, &c., of which he was a founder, awarded him a gold medal for an essay upon 'potashes'.