Those focusing on the exoteric, such as historians of science Lawrence M. Principe and William R. Newman, have interpreted the 'decknamen' (or code words) of alchemy as physical substances.
ðoʊz fˈoʊkəsɪŋ ɔnðɪ ɛɡzoʊtˈɛɹɪk, sˈʌtʃ ɐz hɪstˈoːɹiənz ʌv sˈaɪəns lˈɔːɹəns ˈɛm. pɹˈɪnsaɪp ænd wˈɪljəm ˈɑːɹ. nˈuːmən, hæv ɪntˈɜːpɹɪɾᵻd ðə dˈɛkneɪmˌɛn ɔːɹ kˈoʊd wˈɜːdz ʌv ˈælkəmi æz fˈɪzɪkəl sˈʌbstənsᵻz.