“In general, the long-case clocks’ movements are relatively identical. It is more of a name game when assessing a clock’s value,” says Delaney, who runs his 35-year-old family business with his brother, Sean. He adds that it is the mechanism maker who is the most important in this regard and “often gets all the credit.” However, as is evident from the list of artisans involved with the Louis XVI clock, these pieces were customarily collaborative works, produced by a cadre of craftsmen and apprentices. “There are usually three hands at work,” says Delaney, “the clock maker, who provides the mechanism, a cabinetmaker and an ornamental painter.” Case making was a typically narrow specialty.

According to Christie’s Collingridge, superlative examples by top British makers aren’t often on the market. In fact, only a few auction lots a year are valued at more than $200,000. Such a high-priced item appeared in July 2003 in one of Christie’s London twice-yearly important-clock sales: a Queen Anne tall-case with a month duration (the period before it requires rewinding) made by Edward Banger and Thomas Tompion, the latter of whom is famous for his inventive mechanisms. The clock commanded £621,250 ($1.01 million), tripling expectations. In 2004 a small windfall of tall-case clocks by top makers came up at Sotheby’s as part of a sale of masterworks from the Time Museum—founded by Illinois industrialist Seth Atwood—which had been dissolved when  the city of Chicago wasn’t able to purchase the collection. Assembled over three decades, the 1,500-piece collection included a circa 1685 ebony-veneered tall-case clock with a Roman striking mechanism (incorporating two bells of different pitches) by Joseph Knibb, a maker for King Charles II and the inventor of that type of mechanism. The clock was bought by a British collector for $540,000, more than double its high estimate.

In addition to the mechanical movement and duration (30 hours, 8 days, a month or a year), such complications as calendar, moon and tidal dials or musical movements enhance a tall-case clock’s desirability. Hyde Park Antiques is currently offering a circa 1780 walnut grandfather by the London maker Alexander Cummings with three subsidiary dials—for days of the week, silent or strike, and moon phase—for $160,000. Among the tall-case clocks in Delaney’s inventory is a circa 1830 eight-tune musical-movement example by the Philadelphia maker Thomas Hutchinson that is worth around $50,000. “Musical movements were complicated to manufacture and, as a result, are somewhat uncommon,” says Delaney.

The first tall-cases in America were imported from England in the mid-1680s. These served as models for the earliest home-grown pieces, made a decade later. American production expanded, and by the beginning of the 19th century, so-called grandmother clocks, smaller versions of the grandfather that were based on English 17th-century dwarf clocks, had also become popular. At the end of the 1870s, inexpensive movements made in the U.S. were flooding the market, both Stateside and abroad.

Among the big names in early American tall-case-clock manufacture are Thomas Harland and the four Willard brothers, particularly Simon and Aaron. Harland was the colonies’ first grandfather maker, arriving from England on the ship carrying the tea that was thrown overboard in the Boston Harbor in 1773 and settling in Norwich, Connecticut, where he pioneered the use of standardized and interchangeable parts. The Willards, who were active in the late 18th century, were known for simplifying the grandfather’s action mechanism and for manufacturing the first affordable timepieces in the States.

Collector Todd Keating, who has been acquiring clocks for some two decades, concentrates on Harland and the Connecticut makers descended from his apprentices. These include Daniel Burnap and Eli Terry, the latter known for establishing the first American clock factory, around 1800. “I enjoy following their evolution,” says Keating. Among his holdings is a tall-case by Burnap from the 1790s that has a painted dial, a rarity for the clock maker.