+610+. In the various experimental divisions of the month, as we have seen, a week of seven days has been approached independently in several places (Babylonia, Hawaii, Java, Ashantiland). The basis of this division is doubtless the quartering of the lunation, and it has been reënforced, probably, by considerations of convenience--seven is an intermediate number, six days of work and one of abstinence and rest (holiday) commends itself as a practical arrangement. It appears among the Hebrews as early as the eighth century B.C.;[1003] it may have been derived from or suggested by Babylonian usage, or it may have been an ancient Hebrew custom--data on this point are lacking. In any case the Jewish genius for religious organization seized on the seven-day scheme and wove it into the system of worship. A more important step taken by the Jews was the ignoring of lunar phases (except, of course, new moon as the beginning of the month) and reckoning the week and the seventh day (the sabbath) in a continuous line. We have noted cases in which lunar phases were ignored, but this Jewish arrangement appears to be unique, and its simplicity and convenience have commended it to the world. +611+. _Lucky and unlucky days._ The malefic influences emanating from various objects and resident in the air attached themselves to certain days, and out of the vast mass of experiences in every community there grew up systems of days when things might or might not be done with safety and advantage. There were the great occasions, economic and astronomical, referred to above, and there were particular occurrences, such as a death or a defeat, that stamped a day as unlucky. There are many such beliefs, the origin of which is lost in a remote antiquity. The ancient civilized nations had their codes of luck. Egypt had a long list of unlucky days.[1004] In Babylonia onerous restrictions were imposed on kings, seers, and physicians on certain days (the 7th, 14th, 19th, 21st, 28th) of the sixth and eighth months[1005] (and perhaps of other months). A brief list of days favorable and unfavorable to work is given by Hesiod.[1006] The Roman _dies nefasti_, properly 'irreligious days,' were inauspicious, unlucky.[1007] Similar lists of lucky and unlucky days are found among existing tribes,[1008] and the popular luck codes in Christian communities are numerous and elaborate.[1009] These have done, and still do, great harm by substituting irrational for rational rules of conduct.