When a festival takes place, people assemble together who often have to come long distances. We have spoken above[1132] of the devices adopted in order to ensure that the day of an appointed non-periodic festival shall not be missed. Periodically recurring festivals, which are connected with a natural phase or some occupation, particularly if this is agricultural, are determined as to time, but not accurately. Hence it is already found among the Central Australians that the exact day is fixed by the chief. Such festivals, appointed within certain limits assigned by Nature, are found also among peoples with a fixed calendar, e. g. the Roman _feriae conceptivae_. Significantly enough, these are agricultural festivals which, on account of the change of position of the lunisolar year in relation to the natural year, could not well be regulated by the former. But where a calendar exists, this is the given means of regulating the festival dates so that preparations can be made and the people can assemble at the right time. In the natural and agricultural years the festivals are in the proper sense _conceptivae_; the question is properly to find a means of accurately fixing the day within the short periods given by Nature. This purpose is served by the calculation from the moon. The moon herself has her festivals, especially that of the new moon and, though more seldom, that of the full moon[1133]. Thus the festival times are regulated by the moon. In itself any suitable day of the month can be appointed as a feast-day, but custom and superstition cause certain days to be preferred. Thus the day of new moon, since it was often already a feast-day in itself, was bound to be preferred. The Natchez of Louisiana, for instance, celebrated at each day of new moon a feast which took its name from the animals and plants which the preceding month had principally brought forth, but the greatest festival was that held at the new moon of the first month.[1134] It is a very wide-spread idea that things which are to prosper and grow should be undertaken during the time of the waxing moon, and that anything begun when the moon is on the wane will dwindle and die. Hence the proper time for a festival is the bright half of the moon, and especially the time at which the moon has attained her full shape. It is not only on account of the fair light which costs them nothing that the negroes dance on the nights of full moon. In Dahomey the festivals take place at the full of the moon, and the days are determined by the native government[1135]. In Burma all religious festivals with the exception of the New Year festival, the date of which is regulated in a special manner, take place at the time of full moon[1136]. Throughout Australia, Tasmania, and Melanesia the festivals begin either at full or new moon[1137].