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Google CEO Eric Schmidt

In just the first half of October, public unions poured $471,000 into their energetic campaign to defeat Proposition B, the November ballot initiative that would require increased pension- and benefits contributions from San Francisco city employees.

Campaign contribution disclosures show the largest union donor for this period was the Police Officers Association, which contributed $200,000 on October 14. The second-largest donor was the Service Employee union, which gave $100,000 on October 13 and nearly $300,000 in recent months. The Municipal Attorneys' union gave $50,000, as did the fire fighters. Eight individual San Francisco deputy sheriffs gave small amounts that totaled $1,155.

Meanwhile, the Yes on B camp, led by city public defender Jeff Adachi, reported to the San Francisco Ethics Commission that it received $235,000 in donations from October 1 through October 16. 

The largest single donation came from Google chief executive Eric Schmidt, who gave $75,000 on October 13. George Hume, the chairman of Basic American Food, contributed $50,000 on October 6 and another $25,000 on October 15. Hume, a member of the board of directors of the San Francisco Opera, had contributed $50,000 in July. 

Investor Jon Osterweis, who heads the San Francisco Ballet Endowment Foundation, gave Prop. B $25,000 on October 4.

Angel investor Ron Conway, an early Prop. B backer and also a major backer of the city's sit/lie measure, contributed an additional $5,000 on October 5.

All told, Adachi's campaign has collected $956,000 so far to advance Prop. B. The main union group fighting the proposal, called Stand Up for Working Families, has collected $1.1 million.

A group spearheaded by the San Francisco Labor Council is registered with the Ethics Commission as opposing propositions B and K and promoting measures J and N. That organization has raised $313,000 to date, but its expenditures to defeat Prop. B are not known.