In Scottish folklore, Sunwise or Sunward was considered the “prosperous course�?, turning from east to west in the direction of the sun. The opposite course was known in Scotland as widdershins (Lowland Scots), or tuathal (Scottish Gaelic, lit. northerly), and would have been anti-clockwise. It is perhaps no coincidence that, in the Northern Hemisphere, "sunwise" and "clockwise" run in the same direction. This is probably because of the use of the sun as a timekeeper on sundials etc, whose features were in turn transferred to clock faces themselves. Another influence may also have been the right-handed bias in many human cultures.
This is descriptive of the ceremony observed by the druids, of walking round their temples by the south, in the course of their directions, always keeping their temples on their right. This course deiseal was deemed propitious, the contrary course, tuathal, fatal, or at least, unpropitious. From this ancient superstition are derived several Gaelic customs which were still observed around the turn of the twentieth century, such as drinking over the left thumb, as Toland expresses it, or according to the course of the sun. Wicca uses the idiosyncratic spelling deosil - however, this is not used in any of the three Gaelic languages. _Wikipedia