Digging at historic site in Boise unearths 150-year-old artifacts. What did they find?

One man’s trash is another man’s treasure.

A construction project at the historic Assay Office building in Boise has unearthed artifacts of items that were thrown away and buried as far back as 150 years.

While technically the items are trash, they’re no less valuable for the historical record and provide a window to the past.

“Initially we believed that when they dumped their trash, they dumped it farther off the property,” Chris Shaver, archaeologist for the Idaho State Historic Preservation Office, told me in an interview at the site. “I really wasn’t expecting what we found.”

Found buried in the ground around the Assay Office building, 210 W. Main St., were crucibles and other vessels used by the Assay Office, which melted down ore to separate gold and silver from impurities, leaving behind pure gold or silver, which was then weighed and exchanged with miners for cash or bank notes.

Among the artifacts found were “scorifiers” and “cupels” used in the smelting process, along with a metal bell, a stone ball, broken glass, melted glass vessels, square head nails, grommets, tacks, shotgun shell caps, and even chicken bones and dozens of cow bones, which were sawed, suggesting that they were butchered for food.

One of the more interesting items? A Union General Service Button from around 1855-77 that might have been worn on a frock coat cuff or a cap.

Assay Office history

As I wrote in a column in May, the Assay Office, which today houses the State Historic Preservation Office, is undergoing some restoration.

The Assay Office was built in 1871 and opened in 1872 by the U.S. Treasury Department in Idaho’s early mining days. It served that purpose until 1932, when the need for government-run assay offices was on the decline.

It’s one of Idaho’s most historically and architecturally significant buildings. It’s one of only four buildings in Idaho designated as a National Historic Landmark, which is one step above a listing on the National Register of Historic Places and given only to places that are of national significance.

After 152 years, water infiltration has damaged the building’s basement.

That meant digging a trench around the building and constructing a barrier to keep water away from the building.

In the process of digging on the site, the artifacts were uncovered.

“I asked the crew to give me a call if they found anything,” Shaver said. “I was not expecting what we found. We realized we were looking at something left in the lawn, just a few feet down, for 100 years or more.”

The second floor of the building contained an apartment for the chief assayer and his family, so the artifacts included some “habitation” items, such as buttons made of shell, ivory and metal, tacks, perhaps a coffee cup handle and possibly pieces of a dinner plate. But the bulk of the found items were used in the melting process to extract pure gold and silver.

Making history real

Even Dan Everhart, Idaho State Historic Preservation Office outreach historian, who’s told the story about the Assay Office dozens of times to the public, said holding the objects that he’s talked about for years made it all the more real.

“I’ve been talking about the work of this office for years, but I don’t think I actually had a full realization of it in my mind,” Everhart said. “There’s something about holding or seeing an object to make you totally understand the whole process.”

Blobs of material staining the outside of a crucible allow you to imagine metal and melted rock bubbling over in the furnace. The insides of the little cupels, which seem to be for one-time use, were still stained with the metals that were leached out of the ore.

Many of the artifacts include maker’s marks, which then allowed Everhart to track down their time period.

One broken plate showed just a tiny fragment of a logo with the name “Powell.” State Historic Preservation Office researchers were able to match the name and logo with a company out of Staffordshire, England, named Powell & Bishop, which was so named from 1867-78. The company had different names before and after those years, so the researchers can be certain that the plate was from that time period.

Another crucible carried the mark of the Patent Plumbago Crucible Company, whose name existed only from 1858-81. After 1881, it became the Morgan Crucible Company.

One common mark was J. Taylor & Co., a San Francisco wholesaler of assaying equipment, importing the vessels used in the smelting process from such places as Paris and London.

Everhart imagines the crucibles, scorifiers and cupels making their way via ship from Europe to San Francisco, then by rail to Salt Lake City.

“What’s interesting is that all that material had to come to Boise overland,” Everhart said. “The transcontinental rail line was just completed in 1869, but rail service didn’t reach Boise until 1883, so if you have anything that needs to come into Boise at that time, it has to come up via a freight wagon.”

What’s next

The next step for the artifacts, which they just found the week of Aug. 12, is to clean them up, see what more information can be gleaned from them and document them. Everhart said the artifacts have renewed an interest in creating an exhibit at the Assay Office so that the public can appreciate what the work and life there was like 150 years ago.

Everhart and Shaver emphasized that digging for artifacts on public lands is illegal, so don’t go showing up at the Assay Office with your metal detectors and trowels.

More than just the law, though, Shaver said it’s really a matter of ethics.

“It isn’t just your history,” Shaver said. “It’s all of Idaho’s history. It belongs to all of us. It’s like stealing from the rest of us.”

Further, it’s a matter of preserving the historic record. Shaver said he’s seen people bring in artifacts that they found, but there’s no record of where it was found, in how deep of soil or when it was found. Without those vital pieces of information, the artifact loses its historical value.

“People don’t realize how important that is,” Shaver said. “They think it’s just a trinket, but to us, it’s a historical record.”