As we look ahead to 2011 and time in the future, there is a splendid selection of antique Philadelphia clocks on the market that reminds us of time past. One of the principal human qualities we share with our ancestors is the need to know what time it is.

Although now we may glance more often at our cell phone than a wristwatch, we still have clocks at home and in the office to keep us on time. The most expensive timepieces of the past were stately tall-case clocks, and Philadelphia produced some of the best 18th-century examples.

Pricey then, these clocks still have collectors battling today. On Jan. 22, Sotheby's in New York will sell the Captain John Green Sr. mahogany tall-case clock for an estimated $300,000 to $1 million.

Clocks of this sort have a split personality. They are a fine piece of furniture, usually made of mahogany or walnut and carved by artisans in the best cabinetmaking workshops of the day.

But the clocks also require proper works to function. Some American clocks had expensive works imported from England. Many had insides made right here in Philadelphia by clockmakers who had come to the colonies to seek their fortune.

Leslie Keno, head of American furniture at Sotheby's and a familiar face from PBS's Antiques Roadshow, is delighted to have a superb Philadelphia clock in his forthcoming sale.

"We've set the world record for American clocks four times now, and each one has been a Philadelphia clock," he pointed out. The current record is held by a Peter Stretch tall-case clock sold in October 2004 for $1,688,000; the timepiece is now in the permanent collection at Winterthur Museum in Delaware.

Keno continued, "Always an heirloom, clocks are usually the last piece in a collection that a family wants to sell. They're very anthropomorphic, of course - they have a face, a bonnet, a waist, and feet. And they have a ticker just like we do."

Clock values are determined by many factors - the case-maker's skill, a clockmaker's signature, descent in a prominent local family, and present condition. The Sotheby's estimate reflects strength in all these areas.

Keno said he believed the clock has its original untouched surface and a documented history of descent in the family of John Green, who captained the first U.S. ship to initiate trade with China in 1784.

Carving on the clock case is attributed to John Pollard (1740-87), a London-trained cabinetmaker who began working in Philadelphia about 1765 and probably made this clock about 1770.

"What makes this clock so fine is that Pollard carved the bonnet with great drama," Keno said. "The foliage on top resembles real leaves. It's so naturalistically carved that it scrolls up like a real plant."

The clock's works came from English maker David Patterson. The expert said, "English works were considered the best, and they were the most expensive. People were very status-conscious then, so a clock such as this would have shown that the owner was an important person."

Tall-case clocks are just that - some stand 9 or 10 feet high. Over the years, feet and top pieces were sometimes removed to make them fit into a particular space.

This was the case on a clock sold in November at Freeman's Pennsylvania sale, but the example was so superb in other respects that it still sold for $193,000, well above its $80,000 to $120,000 estimate.

The dial was signed by famous Philadelphia maker Edward Duffield (1720-1801). Dover, Del., dealer James M. Kilvington, a well-known exhibitor in the Philadelphia Antiques Show, bought the clock for a client.

He said, "It's really one of the most important clocks to come on the market in the last few years. It came out of an old Quaker family." The dealer attributes the exquisite carving on the Santo Domingo mahogany case to Nicholas Bernard.

Kilvington also points out the unusual phases of the moon mechanism with a rotating globe, rather than a flat dial. The new owner plans to restore the feet and other missing bits based on similar examples.

Collectors should not be discouraged by the prices for these top clocks in the marketplace. In the next 30 days, there are fine Pennsylvania examples up for auction that may sell in the $2,000 to $15,000 range.

On Jan. 21, Christie's New York will offer a well-carved Chippendale walnut clock, 1760-80, with works by Owen Biddle of Philadelphia, estimated value $5,000 to $10,000. At the top of the signed dial is a painted mechanism showing the phases of the moon.

Pook & Pook in Downingtown will offer a group of regional clocks in a catalog sale Jan. 11. A Pennsylvania Queen Anne cherry clock, circa 1760, has English works that play a tune that will bring an estimated $8,000 to $12,000. A Federal cherry clock with eight-day works, signed by Jacob Guthart of Lebanon, could bring $3,000 to $5,000.