Without documented evidence or further scientific tests, the brick symbol’s age remains speculative. But the bricks themselves are re-used and its mortar appears noticeably different (“...more robust”) than the surrounding wall – so the installation is assumed to post-date the original construction of the building in 1831. The symbol was also constructed as a “Pipe Chase” to conceal utility conduits, which may offer a valuable clue to its date.
The following speculative theory considers circumstantial evidence that suggests a date in the mid to late 1830’s. This is based on the narrow width of the pipe chase, the hand cut bricks, the history of modern utilities in Manhattan, the concerns of the building’s owner, William Colgate, and other factors.
Gas pipe was first laid in New York on Pearl Street in the early 1820’s, with the New York Gas Company being founded in 1823. Gas illumination met early resistance due to safety concerns, but it soon became the standard for lighting in the 19th century (replacing whale oil). Underground water (pumped in from 14th St.) also arrived on Pearl Street in the 1820’s. So construction of the warehouse coincides with the first underground utilities in Manhattan and would not necessarily be inconsistent with a pipe chase installed in the building.
But if gas lines were servicing Pearl Street in the 1820’s, why didn’t William Colgate connect his building in 1831? Colgate welcomed innovation, but he was also a leading firefighter in the city, and we know that he did not install gas lighting at his nearby Dutch Street soap factory in the late 1820’s because it was considered a fire hazard. So he probably held off at 211 Pearl Street for the same reason, even as many merchants were beginning to install gas at the time.
But with improvements to the system (and perhaps some badgering from his merchant tenants), he may have accepted gas lines - possibly within just five years of completed construction. The brick wall encasement would have added a measure of fire safety. And as a double pipe chase, it may have also included water running down from a roof drain.
The location of the pipe chase - near the storefront entrance and rising no higher than the ground floor ceiling - may also be a clue to its use and installation date. Perhaps it lit a mercantile auction space at the front of the building.
It may also be a later addition for electricity (Edison’s first power plant was established just two blocks away on Pearl Street in 1882). Or was it merely decorative - done for a 20th century restaurant or pub? Or is it simply the whim of an unknown bricklayer at some point along the building’s history? The historical record is still blank.
Short of hard evidence, 1837 accounts for gas utility history in Manhattan and Colgate’s fire safety concerns. It also remains within the era of a very similar geometric pattern set in marble and found on the rotunda floor at Federal Hall (1835, Town and Davis) in lower Manhattan. Only mortar analysis at Testwell Laboratories, to be completed by the first week of July, may point towards the truth.

76 Pearl Street is the site of New York’s first protest for historic preservation, with a front-page story appearing in a March 1831 issue of the New York Mirror about an old Dutch house at the address. The caption to an image of the house reads “Built 1626 – Rebuilt 1697 – Demolished 1828”.
What exactly is a ‘world trade center’? Any exchange of goods across continents may amount to ‘world trade’. Although the idea is ancient, it is only in the 1970’s that the name world trade center (usually abbreviated WTC) arose in the United States and Japan, lead by New York City's World Trade Center; which puts together in one location, all the services associated with global commerce, providing networking access between corporations and government.
Demolition work was nearly complete at 215 Pearl Street (1831), when large cracks in the brickwork were found on the wall of adjacent 213 Pearl Street (1831). Tenants of that building were evacuated and DOB officials issued a 'Stop Work Order' at the site, quickly cutting the engine on a 30 ton Hitachi Zaxis 200 excavator. That piece of equipment had replaced low impact hand demolition in the final days. The repair work will likely be complete long before liability and legal issues are resolved.
“Symbols are a language that can help us to understand our past. As the saying goes, A picture is worth a thousand words – but which words” These are the words of Robert Langdon, Prof of Religious Symbology at Harvard University, as he begins a lecture to a hall of students in the opening scene of The DaVinci Code.
St. Mark's Church (at 10th St./2nd Ave) was built in 1799 on land that belonged to Peter Stuyvesant. It's steeple, however, was erected in 1828. Some historical sources credit the design to Martin Euclid Thompson, an architect/builder of the era. Thompson designed the Assay building on Wall St. (The façade of that structure was tranfered to the Metropolitan Museum). Other documents attrubute the steeple to Thompson and Ithiel Town. Town is considered the founder of the country's first architectural firm and he is a prime suspect for the brickwork design at 211 Pearl St., given the striking associations with other designs in his manuscript collection and circumstantial evidence. In many recent surveys of New York City's architecture, however, the steeple is said to be the work of either "Town and Thompson" or "Ithiel Town" alone. 
Among New York’s oldest eating and drinking establishments, the city’s oldest Mexican restaurant belongs to a little know establishment at 213 Pearl Street – Pancho Magico, owned by the Avila family since 1996, who modified the original name, Don Pancho, but have maintained the cuisine and atmosphere of its founding in the 1950’s. It represents another layer of the blocks rich history and is a New York culinary hold-out with development and changing demographics leaving, remarkably in a city of six thousand restaurants, only a handful of long established restaurant landmarks.