The paper addressed to the problem of the solar wind behaviour during the Maunder Minimum. Records on plasma tails of comets would allow to shed light on the physical parameters of the solar wind in the past. We analyse descriptions and drawings of comets to the eighteenth century. To differentiate dust and plasma tails, we address to their color, shape and orientation. Basing on the calculations made by F.A. Bredikhin, we found that deviation of cometary tails from the antisolar direction on average exceeded 10 degrees, that is typical for dust tails. Catalogues of Hevelius and Lubieniecki are also examined. The first indication of plasma tail was revealed only for Great comet C/1769 P1.