In 1855 the famous astronomer of the old Vilnius' observatory, Matvej Gusev (1826-1866) described the stick, which was used as a calendar in the times of the Great Duchy of Lithuania. The signs on the stick represent the sequence of months. They are divided by the symbols of moon phases into weeks of nine days. The calendar is at a luni - solar kind. The usage of such a calendar system in Lithuania of the Middle Ages is confirmed by the features of the archaeoastronomical arrangement on the Birute hill near the seashore in Palanga. The principles of the functioning of the arrangement are based on the fixation of the azimuths of sunset or sunrise, as well as the path of the moon in Meton's cycle. The folk customs of combining spring time feasts with the new moon have been known from historiographic sources. In prehistoric times the lunar period could be used not only for the division of months into separate parts, but also for calculation of the whole year. Wild hoofed animals discard their horns in autumn during the wane. This moment could be used as one of the starting points for the calculation of a year by observing the change of moon phases. The main feasts of such a primitive calendar are the winter solstice, the middle of winter, the spring call, the summer solstice. It means that the source of the lunar calendar lie in the Neolithic period. The way of time setting according to the moon may be found in female jewellery of lst-10th centuries; neck adornments for example consisted of small images of the moon, grouped in triples; the total number is nine, twelve or eighteen. There was no written proof for the passing on of the existing knowledge. Everything was coded with the help of primitive art, folklore and customs. Ancient archetypes have survived up to the present because of the very vital cultural tradition of the settled and farming Baltic ethos, which at the same time represents an ancient approach to the Uni verse. Even presently the moon phases are used to determine the time to begin the majority of farm work. Likewise, main events of a traditional way of life are also associated with moon phases. As a result of the investigation the full picture of the cycle of the year's farm work associated with changes in nature caused by the movement of celes tial bodies is developed.

The article acquaints with the instructions of the Educational Board of the Lithuanian-Polish state. The Board was in force in 1773-1794; its instructions concerned mainly sciences and conformed to the aims of the state's economic policy. The article also presents the ways of implementing these instructions in the Department of physics and mathematics at Vilnius University. Firstly, the way of teaching physics was altered focusing more on the experimental side instead of the previously favoured philosophical one, thus making the subject more practical and of applied character. Students were instructed in how to use the equipment. Secondly, the achievements of mathematics were applied to describe the phenomena of physics; consequently, university teachers had to meet new requirements. Finally, new studies of physics and mechanics models as well as the reference library of the physics study were founded and constantly renewed.