NEW YORK (AFP) - It dates back to 1795 and has been dubbed the oldest time capsule in America. On Thursday, a museum in Boston will open the relic, believed to contain coins and papers.

The Museum of Fine Arts in the north-eastern city will open the time capsule at a press conference, but says numbers are limited due to space constraints and "object sensitivity".

It was originally placed under the State House cornerstone in 1795 by then governor Samuel Adams, one of the founding fathers of the United States, and American Revolution patriot Paul Revere.

The capsule, together with miscellaneous coins, was removed last month, weighed and X-rayed, officials said.

It was last unearthed in 1855, when its contents were documented and cleaned. Additional items were added before it was plastered into the underside of a massive granite cornerstone.

The museum says the capsule weighs 4.5kg and is 14cm long.

Records and X-rays suggest it contains silver and copper coins dating from 1652 and 1855, an engraved silver plate, a copper medal depicting George Washington, newspapers, cards, the seal of the commonwealth and a title page from the Massachusetts colony records.