In 1884, Svante Arrhenius attributed the properties of acidity to hydrogen ions (H+), later described as protons or hydrons.
ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd ˈeɪɾi fˈoːɹ, svˈænt ɚrhˈiːnɪəs ɐtɹˈɪbjuːɾᵻd ðə pɹˈɑːpɚɾiz ʌv æsˈɪdᵻɾi tə hˈaɪdɹədʒən ˈaɪɑːnz ˈeɪtʃ plˈʌs, lˈeɪɾɚ dᵻskɹˈaɪbd æz pɹˈoʊtɑːnz ɔːɹ hˈaɪdɹənz.