IN THE MID-1930S LOS ANGELES, THE FASTEST -growing city in the United States, was desperately in need of two things: water and power. The Boulder (now Hoover) Dam was being built to provide both. Electric power lines would stretch 266 miles from the dam site, on the Colorado River, to Los Angeles. They would carry 275,000 volts of power and provide Angelenos with cheap electricity, but there was a problem.

The city-owned Los Angeles Bureau of Power and Light had up to this time generated AC power for its 285,000 customers at 50 cycles per second. But as electric utilities across the country were rapidly interconnected, a new national standard was established, which L.A.’s new hydroelectric power system would have to meet: 60 cycles.

The change was bound to create problems, so the city earmarked half of the $3.25 million it had budgeted for the changeover for alterations to customer equipment. Most of this money was to go toward modifying motors used in industry. As for household appliances, almost all refrigerators, lamps, sewing machines, toasters, and other devices would run as well at 60 cycles as at 50. But electric clocks would not. The speed of a clock’s motor was entirely dependent on the frequency of the current that supplied it. The change would cause a 50-cycle clock to gain 12 minutes an hour.

The synchronous electric clock was ubiquitous in the 1930s, expensive and highly prized in the days before crystal-controlled, battery-operated timepieces. There were about 125,000 of them in greater Los Angeles in 1936. A mantel or grandfather clock was the centerpiece of almost any well-appointed living room, and businesses used electric clocks both in the workplace and on signs and storefronts. Almost every school, hospital, department store, and factory in the city had a system of electric clocks. Each of these timepieces would have to be converted, usually by altering the gear train, or replaced before the Boulder Dam power reached Los Angeles.

In what was surely one of the oddest public works campaigns in its history, the Bureau of Power and Light gave the E. W. Reynolds Company a contract to solve the problem by replacing or converting every electric clock in Los Angeles, free of charge to the owner. Reynolds rented a large factory and hired about 75 experienced clock repairmen. It then used proficiency tests to cull an additional staff of 125 unskilled workers from a pool of several thousand applicants. Each of these unskilled workers was trained, over the course of six weeks, to change one make of electric clock from 50-cycle to 60-cycle operation. For common clocks, manufacturers were asked to build conversion kits providing new gear works. The factory’s own machine shop would cut gears for more exotic models.

District by district, as the frequency change was phased in across Los Angeles, the power company sent letters to customers and placed notices in newspapers and on the radio. Residents were asked to bring their electric clocks to neighborhood collection centers. The clocks were then trucked to the factory to be cleaned, converted, lubricated, and tested and were returned to their owners within five days. If a clock could not be converted, it was replaced with one of comparable value. At the same time, the professional clock repairmen worked on a host of commercial timekeeping devices.

It took 18 months, but the work was finished right on time, in October 1936. When it was all over, the Bureau of Power and Light faced an unusual problem. What do you do with 55,000 nonconvertible 50-cycle clocks? The city ended up dumping most of them into Los Angeles Harbor.

The unskilled workers didn’t fare much better; they were given their tools and sent back to the Depression’s unemployment lines. Their training, limited as it was to only a single model of clock, was hardly the basis for further employment elsewhere. It is believed that none of them ever worked in clock repair again. Their training, it seems, was as obsolete as all those 50-cycle clocks.