Walking into the office of archaeologist Donald Keith is like opening the door to your neighbor's garage. It's not particularly messy, but there's plenty of unidentifiable old stuff, scattered mystery objects among the boxes, hoses and electrical gadgets.
But rather than decades-old mementos, the hidden treasures here are centuries-old artifacts from ships of early explorers.
Among the artifacts are an 800-pound bronze cannon with a royal crest, pewter plates and brass rings taken in July from a sunken ship in Matagorda Bay. The ship is believed to have belonged to the French explorer LaSalle, who claimed the Mississippi Valley for King Louis XIV in 1682. Leaders in the archaeological project said they expect the artifacts, once identified and dated, to help prove the ship to be LaSalle's.
Ships of Discovery staff and volunteers, headed by Keith, are responsible for conservation of the first artifacts recovered as part of the Texas Historical Commission project. The conservation work performed by Ships of Discovery, housed at the Corpus Christi Museum of Science and History, allows the artifacts to be studied without deteriorating further, Keith said.
"What we do is 90 percent of the effort" on an archaeological project, said Keith, president of Ships of Discovery, which usually studies explorers' ships from the late 15th and early 16th centuries. The objects must be stabilized and cleaned by mechanical and chemical methods so corrosion is halted, Keith said. Often there isn't documentation as to which conservation treatments work best, so it's up to the staff to find them.
"The real problem is, in their hundreds of years in the sea they have reached an equilibrium with the sea water, absorbed the salt or chloride. Removing the chloride is the trick," Keith said.
Cleaning time depends on how long objects were immersed, what they're made of, their condition and the environment, like the condition of the water and how deep they were buried. Wrought iron is the hardest to treat, Keith said.
Pewter is proving difficult but copper and lead are easier. Combinations of materials - such as four small iron spots on the ornate bronze cannon that react to cleaning methods differently - also pose problems, Keith said.
"All conservation is a balancing act between cleaning, which usually removes some of the surface of the object, and preservation, which tries to keep it all together," Keith said. Keeping the surface of the cannon intact may mean leaving behind evidence of its years under water, he added.
A small group of objects made of copper alloys such as brass or bronze are in the final stages of treatment. The small items - brass rings, a whistle, a belt buckle, the hilt of a sword and a pot handle - have been cleaned, photographed, measured and drawn. Every detail of their treatment has been logged.
The first step in removing the chloride is repeated baths in deionized water. "Basically, the extremely salty artifact is put in pure water and the salt tries to reach equilibrium with the water, so the salt distributes itself in the water," Keith said.
After the chloride level in the water levels off, the water is changed. After chloride level in fresh water rises and levels off, the water is changed again. The process continues until the level of chloride in the pure water no longer rises.
The process can be enhanced by using electrolytic reduction, Keith said. The chlorides are negatively charged. A mild negative charge is given to the object. Metal plates placed in the bath with the object are given a positive charge and the object pushes the chloride into the solution.
Such a bath is being prepared for the bronze cannon, which is adorned with dolphin-shaped handles and floral decorations. Last week it was suspended in a vat of tap water and sodium carbonate, used to "adjust the pH (level of acidity) levels and make the environment a little friendlier to it," Keith said.
Most of the cleaning and chloride removal on the cannon should be accomplished in a couple of months, Keith said, though there may be some problem areas, such as the four iron-filled holes.
The two dozen pewter plates recovered from the shipwreck also are posing problems in the lab. "We've got (preservation methods) pretty well down for iron, bronze and copper. Pewter is a new experience for us," said Worth Carlin, a retired chemist and volunteer with Ships of Discovery.
One plate, severely corroded, was sacrificed for testing, said Carlin, who compared results of three tests he performed on scraps of the plate. The piece he electrolized for three days looks best, and he must decide, he said, if that's the method he'll use to conserve the whole batch.
He'll try other formulas before he makes a decision. The plates have lasted 300 years, and he'd like them to make it hundreds more, he said. "We can afford to wait around a while (to get it right)."
The artifacts from the shipwreck -goods necessary for settlers, not riches - will remain at the local museum as part of a temporary display until project research is complete, said museum director Rick Stryker.
The shipwreck find is significant because it represents the French interest in settling this area, juxtaposed with the Spanish interest represented by the museum's display of the 1554 shipwreck found off Padre Island, Stryker said.
According to the Texas Historical Commission, the site is the oldest French colonial period shipwreck found in the New World. Excavation is expected to take two more field seasons, mostly summers, to clear the ship of artifacts and then raise the hull, said commission director Curtis Tunnell.
The remaining artifacts would overwhelm the small local lab and will be taken to another facility, such as Texas A&M University, Tunnell said.
As the project nears completion, the Texas Historical Commission will take applications from facilities interested in housing the shipwreck exhibit. It is likely the artifacts will travel as an exhibit before being permanently placed by the commission, as was done with 1554 shipwreck exhibit, Tunnell said.
"All of this will be playing out over the next several years," Tunnell said. The permanent home for the artifacts must have adequate space and safety measures, Tunnell said. It also will be as near as possible to the shipwreck site and a place where the maximum number of people can see it, he said.