Water clock

A water clock was a common device for telling time. An early version of water clock was called a clepsydra. The Neverwintan water clock was a noted model of water clock made in Neverwinter on the Sword Coast North that was renowned for its regularity.

Description
A typical household water clock worked by allowing water to drip from one reservoir into another. A float atop the water would indicate the hour and the water could be tinted for better visibility. For example, the household water clock sold by Aurora's had glass reservoirs and a glass float, and was set in a heavy marble frame to limit bumping and sloshing that would upset the time. Felt on the bottom prevented damage to furniture. It could fit on a tabletop of mantel and was valued at 20 gp. Hence, water clocks could be quite big and bulky, typically weighing up to. Moreover, they needed a steady supply of water and had to be kept absolutely motionless for a regular rate of drips. Even so, a basic water clock was typically only accurate to within half an hour per day since it was set last. On worlds where water clocks were still a rarity, they could cost as much as 1,000 gp.

The more advanced Neverwintan water clocks involved gear mechanisms. An example Neverwintan water clock comprised a tube of glassteel mounted on a wall with a clock-face attached. Water was piped through the wall at a specific rate and flow and poured into the tube, before it was drained into a small cup. It would fill in 1 minute and then tip over, pouring the water into the bottom reservoir of the glassteel compartment, and a minute hand ticked forward on a clock face. After an hour, the reservoir was emptied and a gong was rung, which could be a magical effect. It was a delicate device and any disturbance or attempt to remove or relocate one would ruin it. A Neverwintan clockmaker would need to reinstall and recalibrate it and ensure the correct water flow before it would function properly again. Naturally, they were not particularly portable, especially into such places as the Underdark. However, provided they had a steady supply of water, a Neverwintan water clock was typically accurate to within 5 minutes over a year. A regular water clock could be as big as a merchant's coffer and could be carried in two hands by one person. A basic model cost 150 gp, but they could be more expensive,  with an ornate Neverwintan water clock valued at 500 gp.

Availability
Neverwintan water-clocks were recognized, sought after, and in use by sophisticated sorts all over Faerûn by the mid–14 century DR. They were fashionable in the townhouses of the more civilized realms.

Aurora's Emporium sold its household water clocks through its catalogue in the mid-to-late 1400s DR.

Water clocks were also developed by the Shou in Kara-Tur, and were used in Shou Lung and T'u Lung.

Usage
In T'u Lung, most villages had a water clock that was set at sunrise, so local time tended to vary with location and time of year. In the capital city, Wai, a special water clock was fed by an aqueduct and never reset or adjusted to the season or sunrise. It measured the official "true time", which governed the Emperor's schedule.

On other worlds, as most folk had no need to know the time precisely, water clocks were largely only toys for the rich and instruments for magical studies, so they tended to be found in mage's workshops.

Reputation
Neverwinter was renowned for the accurate and high-quality water clocks crafted by its artisans. This gave rise to the phrase "by the clocks of Neverwinter", used to swear something to be completely true and honest, declare something to be precise and accurate, or complain something was needlessly perfectionist and pedantic. Neverwintan water clocks set the standard for precision in Faerûn and water clocks were in general closely associated with the city.

"The turning of the waterclocks", or simply "waterclock", referred to a time in the early afternoon, approximately 2 pm on Earth. Spellcasting and other magical works that involved emerald were most effective or 20% more likely to succeeded if performed within half an hour of this time.

Something that occurred all day long was said to run "the waterclock around". For example, if people were on duty at all hours, they were said to "serve the waterclock around in shifts".

There was a sentiment than even a water clock run dry told the correct time twice a day.

History
A musical clepysdra was demonstrated at the Palace of the Phoenix in Cursrah in. It was a marvel to the guests and they called for an encore performance. Its remains were found in the, but the secret of its design had seemingly been lost.

In the late 12 century DR in Neverwinter, Saborn Rendel, a master craftsman of waterclocks, and an elf mage known as Lucan Greenharrow established the Waterclock Guild. Together, they constructed splendid and highly accurate timepieces, but Lucan's magic was the secret of their success. Their work even extended to summoning and binding water elementals and constructing a guildhall and a mausoleum with a complex of gears, waterfalls, and traps powered by these elementals.

In Skullport, the gnomes Tohkkal and Tykkyl Burrwarden of Clockwork Wonders worked with Master Karl Gustavis Gearwizzen and two other Gondsmen to build a great waterclock. Their aim was to create an accurate method of timekeeping in the subterranean city and thereby improve trade. They loosely copied the design of a Neverwintan water clock and it was finished shortly after Halaster's Higharvestide in 1369 DR.

Notable Water Clocks
The unique clepsydra known in the time of the Calim Empire was a tall contraption topped with a fountain. The water ran down through many slender pipes so it could produce drops and form jets. These in turn caused wheels to spin, bladders to compress, cups to fill and tip, and counterweights to drop. All of this was for not for telling time, but for playing music, operating instruments such horns, strings, flutes, drums, and even bagpipes, not to mention the background gurgling.

The Waterclock of Skullport was built within a massive stalactite hanging from the roof in the city's central cavern, between the Lower and Central Trade Lanes; it could be seen from anywhere in the ward. It told the time with respect to dawn, highsun, dusk, and midnight and even the tendays, months, and intercalary festivals of the Calendar of Harptos. The Gondsmen kept shifts around the waterclock, as the saying went, to provide ready maintenance, such as filling reservoirs, oiling mechanisms, and repairing, adjusting, and replacing parts, springs, and balances as needed—Skullport's damp air and otherwise poor environment didn't help. For security, it had magical wards and mechanical traps—would-be saboteurs had lost fingers or limbs, shot with darts, and electrocuted, while spellcasters might see their spells hurled back at them, and it was apparently immune to disintegrate thanks to Gond, while the Skulls of Skullport investigated any trouble around it.

Water clocks were installed in the temples of a variety of faiths:
 * Bard Keep of the Church of Oghma in the Silver Marches. Broken, this water clock was left behind when the monks abandoned the place.
 * The Grotto of the Queen, a temple to Umberlee in Lathtarl's Lantern. This wall-mounted Neverwintan water clock played a magical gong sound.
 * The Temple of Wisdom, dedicated to Garl Glittergold, at the Friendly Arm on the Sword Coast. Especially large, this Neverwintan water clock stood in the courtyard and had a compartment big enough for Bentley Mirrorshade to hide in.

They also appeared in palaces, for example:
 * Castle Obarskyr in Suzail, Cormyr. Installed in the antechamber circa 1369 DR, it had silvery globes for floats.
 * The palace of King Zalathorm Kirkson in Halarahh, Halruaa. It comprised a tall cylindrical glass container with floating balls of many hues.

Naturally, places of study and research had water clocks too:
 * The College of Conjuration and Summoning in the drow city of Sshamath in the 1370s DR. Installed in the scriptorium, it was a simple cut-glass bowl hanging from the ceiling that dripped water into a pan below and marking the quarters of night and day. It was considered a thing of the World Above and not of much practical use in the Underdark.
 * The College of Ancient Arcana under Q'arlynd Melarn also had a water clock in the lecture hall at that time.
 * A library tower in Halarahh, Halruaa, chimed on the hour.
 * Khelben Arunsun had a Kara-Turian water clock in one of his laboratories in Waterdeep.

An ornate Neverwintan water clock was found in the treasure hoard of the black dragon Ebondeath in his lair in the Mausoleum of the Ebondeath beneath the Uthtower.