10PM

10PM marks the fifth night hour of the planetary hour system, reckoned from the temporal hours the tradition actually uses rather than the fixed sixty minute clock hour a modern reader assumes by default. A temporal hour divides the interval from sunrise to sunset, or from sunset to the next sunrise, into twelve equal parts regardless of season, so a summer night hour and a winter night hour are different lengths in real minutes even though both count as one twelfth of the night span; only at the equinox, when day and night are equal, does the temporal hour match the clock hour closely enough to set a single fixed table like this one.

The system draws on only the seven planets visible to the naked eye, ordered by the Chaldean sequence of their apparent orbital speed as seen from earth, Saturn slowest, then Jupiter, Mars, the Sun, Venus, Mercury, and the Moon fastest, and that sequence repeats continuously through both the twelve day hours and the twelve night hours. Because a full day runs twenty four hours and the sequence repeats every seven, the ruling planet of a day's first hour shifts forward from one day to the next in a fixed order, and it is that first hour planet which actually names the day of the week: Sunday for the Sun, Monday for the Moon, Tuesday for Mars, Wednesday for Mercury, Thursday for Jupiter, Friday for Venus and Saturday for Saturn. On a Sunday, by that reckoning, 10PM falls to Mercury, the fifth hour of the night.

10PM, the fifth hour of the night on a Sunday, belongs to Mercury. Mercury's hours were kept for communication, study and skilled craft: writing, teaching, contracts of business rather than land, travel, and divination itself, since Mercury was read as the planet nearest the working of the mind. The grimoire tradition treats Mercury as changeable, taking on something of the character of whatever planet stands nearest it. Practitioners were counseled to match the work to the hour wherever the two could be arranged together, choosing an hour whose ruling planet suited the operation in hand rather than acting in whatever hour happened to be free; a working that fit its planet well was held to draw strength from the hour, while one that fought the ruling planet's nature was held to labor against it.

Because the same planet returns roughly every seventh hour through the whole day, Mercury also rules 5AM, 8AM and 3PM elsewhere on this reference Sunday, so a practitioner without access to 10PM specifically could look to those instead for work of the same character. The hour sits inside a wider correspondence system built around the same seven planets: Mercury is paired with the metal an alloy standing in for quicksilver, mercury itself being liquid at ordinary temperature, with orange or a mix of colors, and with Wednesday, the weekday carrying its name in full as well as its first hour. A working timed to 10PM was traditionally strengthened further by choosing Wednesday itself and by using that metal and color in the object the working required, and the same logic timed ordinary practical acts as well as ritual, from gathering herbs held sacred to a planet to medical treatments believed to answer best to its temperament.