ɪn pɚtˈɪkjʊlɚ, ˈɔɪlɚɹ ænd hɪz kəntˈɛmpɚɹˌɛɹiz dʒˈiːn dɐlˈɛmbɚt, lˈuːi lˈæɡɹeɪndʒ, ænd ˈʌðɚz nˈoʊɾɪst smˈɔːl vˌɛɹɪˈeɪʃənz ɪn lˈæɾɪtˌuːd dˈuː tə wˈɑːblɪŋ ʌvðɪ ˈɜːθ ɚɹˈaʊnd ɪts pˈoʊlɚ spˈɪn ˈæksɪs.
In particular, Euler and his contemporaries Jean d’Alembert, Louis Lagrange, and others noticed small variations in latitude due to wobbling of the Earth around its polar spin axis.