[en] Results of solar wind measurements by different spacecraft are not always in full accord. Such measurments are in general not from one and the same distance r from the sun, nor are they taken at the same phase of the solar activity cycle. One would like to be able to discriminate between spacecraft calibration effects on the one hand, and solar wind variations which reflect true spatial gradients or changing boundary conditions at the sun on the other hand. Accordingly the authors examine the possibility of reconciling the apparent discrepancies. First, density measurements are compared and their differences related to the velocities with which they have been sampled. Further, proton temperature gradients obtained from Helios 1 and Mariner 2 are compared and it is suggested that the different results are due to stream-stream interactions in the solar wind. A brief summary of the more obvious as well as the subtle effects velocity sampling has on the evaluation of some solar wind parameters and their gradients is given. (Auth.)