[en] Four aspects of the free surface of liquid ⁴He at very low temperatures are discussed: (i) The surface tension (sigma) of liquid ⁴He purified to contain 0.4 +- 0.2 parts per 10⁹³He was measured as a function of temperature in the range 0.02 less than T less than 0.35⁰K. It was found that the data agree with Atkins' theory of surface excitations (''ripplons'') for the temperature dependence of sigma(T). (ii) A theory of scattering of a low-energy ⁴He beam at the superfluid ⁴He surface is developed which results in an effective one-body Schrodinger equation. The calculation is variational in the spirit of Feynman's treatment of bulk excitations in liquid ⁴He and assumes that each absorbed atom produces a single excitation. For a given density profile n(z), the probability of elastic scattering R is calculated by the numerical solution of this integrodifferential equation and compared with recent measurements. It is concluded that the single-phonon theory must be modified to allow for the production of ripplons. By neglecting to symmetrize the trial wave function, it is easy to find analytic forms for n(z) which give excellent agreement with experiment. (iii) The scattering of a pure ³He beam is of interest because it can be analyzed with the unsymmetrized theory. The technical question of generating a pure ³He beam is examined via a simple model and some preliminary data is presented. (iv) Recent measurements of the surface sound velocity and surface tension over a wide range of concentrations (30 ppB to 300 ppB) as well as earlier data, are used to obtain new values for the effective mass M = (1.45 +- 0.1) m₃ and binding energy e₀/k/sub B/ = 2.22 +- .02⁰K of the adsorbed ³He. In addition the effective interaction between the ³He quasiparticles is found to be predominantly positive, a condition unfavorable for superfluidity