Correction ((10), 1e membre) : « ( d x ′ 2 + d y ′ 2 + d x ′ 2 ) {\displaystyle \left(\operatorname {d} x'^{2}+\operatorname {d} y'^{2}+\operatorname {d} x'^{2}\right)} » → « ( d x ′ 2 + d y ′ 2 + d z ′ 2 ) {\displaystyle \left(\operatorname {d} x'^{2}+\operatorname {d} y'^{2}+\operatorname {d} z'^{2}\right)} » (coquille)