Who could imagine that the slide rule, once ubiquitous in high school mathematics classes, would be used to figure the odds at horse races or to calculate the alcohol content of a barrel of beer? But the innocuous-looking slide rule has a 400-year-old and storied history. Old Palo Alto resident Tom Wyman knows it well.

Wyman, a retired geologist and mining engineer, has collected slide rules ever since he found a particularly elaborate set in a bombed-out shipping complex in Tokyo Bay during World War II. His 60-year collection now encompasses 700 to 800 slide rules, some dating back to the early 1600s, when the earliest slide rules appeared.

"There are more in the basement that I haven't told my wife about," he said, smiling.

In his home office, Wyman likened his collection to his "children." An eight-foot-long slide rule used in classrooms hangs from the wall.

Carefully unwrapping specimens from his precious collection, he displayed a square boxwood slide rule that dates to 1683 and was used to calculate the taxes on casks of wine and beer. There are specialized slide rules for calculating electrical equations and engineer slide rules; helical scales, with numbers arranged like a coiled spring, measured with the accuracy of a 40- to 50-foot scale but with the length of only a few inches.

Among the more whimsical: drink-mixer slide charts and circular slides, such as the Race-o-matic, a round, pocket-sized scale used to handicap greyhound, harness and thoroughbred horse races.

Wyman is fascinated by the slide rule because it figured prominently in history — the Industrial Revolution depended on slide rules for mechanical calculations — and for what it reveals about how people lived. Everything that was measured, from hides to whiskey, can reveal much about diet and lifestyle in particular periods of history, he said.

The slide rule helped James Watt invent the steam engine. And English-American revolutionary and pamphleteer Thomas Paine founded some of his philosophy on his experiences using a slide rule as an excise-tax officer.

In his adolescence, Watt was an instrument maker, according to Wyman.

"He designed slide rules for his technicians. He was the first one to devise an engineer slide rule in the late 1700s," Wyman said.

Paine used the slide rule to calculate taxes on manufactured goods. The tool helped calculate not only the quantity of liquids but also the alcohol content in barrels of spirits.

Although the slide rule's calculations were accurate, the tax numbers often were skewed — depending on how many pints of beer the officer had finagled out of a hapless innkeeper, Wyman said.

Paine complained about officers' low wages that caused them to take bribes to make extra money. His efforts cost him his job in 1774 and he immigrated to America thereafter. The rest of his story is history, Wyman said.

Wyman regularly writes papers on the topic. This week he is traveling to England to lecture on Samuel Pepys, a 17th-century English naval administrator and Member of Parliament who used the slide rule to calculate the number of board feet delivered to the Navy, rooting out shorted deliveries. He is now famous for his diary, Wyman said.

Wyman estimated he has published as many as 30 scholarly papers on the subject — not bad for a man who was once a "powder monkey" in Eastern coal mines, delivering cases of dynamite and fuses to miners.

A native Palo Altan, he attended Walter Hays Elementary, the now-defunct Channing School, Jordan Middle School and Palo Alto High School. He received degrees from Stanford, studying mining engineering and geology. He worked his way up from the bottom, toiling as a roughneck on oil rigs to working as a geologist and executive positions in shipping, representing his company internationally.

Locally, he and wife Ellen are known for their work with the Friends of the Palo Alto Library. The Wymans helped book sales mushroom to more than $100,000 a year. He is also a former Palo Alto Library Commission chair. In 2005, the couple received an Avenidas Lifetimes of Achievement award for their years of local public service.

The slide rule retired from the engineer's pocket in the 1970s, replaced by the electronic calculator. Now, computer programs make millions of calculations in seconds. The slide rule might be relegated to the role of museum piece, but Wyman said something is lost that is irreplaceable.

"We lost a sense of numeracy — the mathematical equivalent of literacy — when we lost slide rules," he said.