&Solar Physics BRussian Ksolar flare, magnetic field// Preliminary results on the solar flare of 29 March 2001 of importance X1.7/1B are presented. The echelle Zeeman spectrograms of the flare were obtained on the horizontal solar telescope of the Astronomical Observatory of the Kyiv Shevchenko University. Measurements of the lon¬gitudinal magnetic field strength B_∥ by the «center of gravity» method showed that the field observed in the Fe I 630.25 and Fe I 630.15 lines increased during the first 8 min of the flare, including the flare peak, and systematically B_∥(630.25) > B_∥(630.15). The Stokes I and V profiles of Fe I λλ 617.33 and 602.41 lines display a correlation between the intensity fluctuations in the «red» and «violet» wings of two lines and in the adjacent continuum. There is a moderate positive correlation for Stokes I (to r = +0.54, p Full text (PDF)