In 1914, a year before he was killed in action at Gallipoli, the English physicist Henry Moseley found a relationship between the X-ray wavelength of an element and its atomic number.
Pada tahun 1914, setahun sebelum ia tewas dalam aksi di Gallipoli, fisikawan Inggris, Henry Moseley, menemukan hubungan antara panjang gelombang sinar-X unsur dengan nomor atomnya.