In 2010, Tom Mullaney found himself way out in the suburbs of London. A woman there wanted to show him a Chinese typewriter. She was going to be renovating her house soon, she told him, and it needed a new home.

Dr. Mullaney, a professor of Chinese history at Stanford University, had spent years searching the globe for Chinese typewriters, wondrous machines capable of printing thousands of Chinese characters while remaining small enough to keep on a desk.

The typewriter, 50 pounds of metal frame and levers, was one of a dying breed. If he didn’t save it, would it wind up on a scrapheap?

It went into a suitcase and he took it back to California, where it joined a growing collection of Asian-language typing devices that he’d hunted down.

But there was one typewriter that Dr. Mullaney had little hope of ever finding: the MingKwai. Made by an eccentric Chinese linguist turned inventor living in Manhattan, the machine had mechanics that were a precursor to the systems almost everyone now uses to type in Chinese.

Only one — the prototype — was ever made.

“It was the one machine,” he said recently, “which despite all my cold-calling, all my stalking, was absolutely, 100 percent, definitely gone.”