The possibility is demonstrated of studying large-scale interactions in the solar wind, using all the available data over a continuous range of distance. The magnitude of the fluctuations of the proton density and the temperature about their mean values and their correlation diminish closer to the sun. The dependence of mean values on the flow speed and the heliocentric distance is dealt with by using mean value relations. Continuous distance coverage is obtained by using data from the Helios 1 spacecraft. Indications are that the fast and intermediate solar winds are more uniform than the slow wind. For the latter, no clear correlation is found between temperature and density fluctuations, over the whole range 0.3-1.0 AU.