def _Conductivity(rho, T):
    """Equation for the electrolytic conductivity of liquid and dense
    supercrítical water

    Parameters
    ----------
    rho : float
        Density, [kg/m³]
    T : float
        Temperature, [K]

    Returns
    -------
    K : float
        Electrolytic conductivity, [S/m]

    Notes
    ------
    Raise :class:`NotImplementedError` if input isn't in limit:

        * 600 ≤ ρ ≤ 1200
        * 273.15 ≤ T ≤ 1073.15

    Examples
    --------
    >>> _Conductivity(1000, 373.15)
    1.13

    References
    ----------
    IAPWS, Electrolytic Conductivity (Specific Conductance) of Liquid and Dense
    Supercritical Water from 0°C to 800°C and Pressures up to 1000 MPa,
    http://www.iapws.org/relguide/conduct.pdf
    """
    # FIXME: Dont work
    rho_ = rho/1000
    kw = 10**-_Kw(rho, T)

    A = [1850., 1410., 2.16417e-6, 1.81609e-7, -1.75297e-9, 7.20708e-12]
    B = [16., 11.6, 3.26e-4, -2.3e-6, 1.1e-8]
    t = T-273.15

    Loo = A[0]-1/(1/A[1]+sum([A[i+2]*t**(i+1) for i in range(4)]))      # Eq 5
    rho_h = B[0]-1/(1/B[1]+sum([B[i+2]*t**(i+1) for i in range(3)]))    # Eq 6

    # Eq 4
    L_o = (rho_h-rho_)*Loo/rho_h

    # Eq 1
    k = 100*1e-3*L_o*kw**0.5*rho_
    return k