The dynamics of relaxation and transformation of the structure of convective flows of a weakly stratified liquid are investigated by optical methods in the case of uniform lateral heating. The experiments were carried out for different (small (S = 0.22%) and high (6.5%) basic-salinity values, for which the main parameters of the medium (the thermal expansion coefficient, the saline compression coefficient, the kinematic viscosity, the thermal diffusivity, and the salt diffusion coefficient) differ somewhat. It is shown that the dependence of the structure parameters on the properties of the medium is weak, which justifies the possibility of extrapolating the data of bench experiments on highly stratified liquids to weakly stratified natural systems, such as the atmosphere and the hydrosphere. It is shown that, over a wide range of the experimental parameters, the length and height of the convective cells vary at a constant rate.