At the beginning of the current century, P. Wilski, orienting a 1090 m deep mine in Příbram, found that measurements of the adjacent connection angles at air movement in the shaft and in the absence of this movement give a discrepancy of 11'31”. Based on this and on the data of visual observations of air movement in the shafts, he put forward a hypothesis about the helical movement of air along the shaft, affecting the magnitude of the weight deviation a. He determined the magnitude of the deflection a using the formula. However, firstly, with helical motion, taking into account the existing velocities, the expected deviation of the plumb line is significantly greater than that observed in practice. Secondly, and this is the main point, mine workers, who have the opportunity to observe the nature of air movement in the shafts every day, do not detect helical motion in an explicit form, which also casts doubt on the validity of the hypothesis.