Sedan Chair Carriage Clock ( French, ca. 1900)

Lighthouse Mantel Clock ( French, ca. 1880) Paris Fountain Clock and Barometer ( French, ca. 1890) Floating Turtle Clock ( French, ca. 1900)

A simulated lantern atop this lighthouse- style clock oscillates between green, clear and red glass. The case has a bright, twotone gilt finish. “When he handed the clocks back to me, they looked like they just came from the factory,” Tatum said.

The pre - Mclemore lighthouse was missing its crowning detail. “He made that little flag, and he said he made that when he was stoned,” Tatum recalled. But, Tatum added, “he hand- filed it, and whatever state of mind he was in, he made it correct. He always made it correct.”

This miniature likeness of stately fountains that offered drinking water to 19th- century Parisians was purchased by Tatum “as is”: a monochrome brass,

This remarkable table clock announces the hour via a floating turtle in a pewter bowl: Fill it with water, drop in the turtle and, presto, the animal glides to one of the numerals around the pan’s rim. “He’s going to float to whatever time it is,” Tatum said. “It never disappoints you.”

The turtle is pulled to the correct time by a magnet hidden beneath the bowl.

“When I bought that clock, it did not have the right turtle,” he said. “It was too heavy to float.” Another friend carved a lighter specimen. The finishing touch: “John B. took a magnet off his refrigerator and inserted that into the turtle.”

A rare misstep also left its mark. After Mclemore fixed the clock, he tested a new, lighter turtle. “We didn’t know there was a leak in the bottom of the pan,” Tatum recalled. “He filled it up, went to bed, and came back to the shop and there was water on the movement,” Tatum explained, referring to the clockwork mechanism. “Wasn’t expecting

One of the podcast’s mysteries: Did Mclemore’s use of mercury poison him?

He liked bygone techniques, notably fire gilding, in which gold and mercury are combined; the mix is torched to vaporize the mercury, leaving only a gold finish. Mclemore scarcely protected himself from the ensuing fumes.

For most of Tatum’s clocks, Mclemore used electroplating, a process involving dangerous materials. Metal is refinished in a solution that is part toxic potassium cyanide. This method may not produce fumes, but the vats used would contain extremely hazardous chemicals.

Several such brews were required to refinish this fanciful miniature sedan chair. It was a uniform brass tone when Tatum bought it, and he calls its restoration “the crowning jewel of John B.’ s work.”

Mclemore spent weeks masking off portions of the clock’s motifs by applying a lacquer seal. When plated in the cyanide mixture, the exposed, unlacquered sections acquired their intended finish. Then the lacquer is removed, applied to different sections and placed in a new cyanide mixture. The process is repeated several times until all the finishes are applied.

The replated details glimmer in pure and tinted golds and silvers, the result of tedious work. Upon finishing the clock, Mclemore said: “Tatum, I’ll never do that again.”