nd what is the explanation
of their order?

The late well-known astronomer, R. A. Proctor, gives the explanation as
follows:--

"The twenty-four hours of each day were devoted to those
planets in the order of their supposed distance from the
earth,--Saturn, Jupiter, Mars, the Sun, Venus, Mercury, and
the Moon. The outermost planet, Saturn, which also travels in
the longest period, was regarded in this arrangement as of
chief dignity, as encompassing in his movement all the rest,
Jupiter was of higher dignity than Mars, and so forth.
Moreover to the outermost planet, partly because of Saturn's
gloomy aspect, partly because among half-savage races the
powers of evil are always more respected than the powers that
work for good, a maleficent influence was attributed. Now, if
we assign to the successive hours of a day the planets as
above-named, beginning with Saturn on the day assigned to that
powerful deity, it will be found that the last hour of that
day will be assigned to Mars--'the lesser infortune,' as
Saturn was 'the greater infortune,' of the old system of
astrology--and the first hour of the next day to the next
planet, the Sun; the day following Saturday would thus be
Sunday. The last hour of Sunday would fall to Mercury, and the
first of the next to the Moon; so Monday, the Moon's day,
follows Sunday. The next day would be the day of Mars, who, in
the Scandinavian theology, is represented by Tuisco; so
Tuisco's day, or Tuesday (Mardi), follows Monday. Then, by
following the same system, we come to Mercury's day
(Mercredi), Woden's day, or Wednesday; next to Jupiter's day,
Jove's day (Jeudi), Thor's day, or Thursday; to Venus's day,
Vendredi (Veneris dies), Freya's day, or Friday, and so to
Saturday again. That the day devoted to the most evil and most
powerful of all the deities of the Sabdans (_sic_) should be
set apart--first as one on which it was unlucky to work, and
afterwards as one on which it was held to be sinful to
work--was but the natural outcome of the superstitious belief
that the planets were gods ruling the fates of men and
nations."[136:1]

This theory appears at first sight so simple, so plausible, that many
are tempted to say, "It must be true," and it has accordingly gained a
wide acceptance. Yet a moment's thought shows