A sine qua non, or essential condition, for taking a top-level position in the Rawlings-Blake administration is never saying why you left it.

Or so it seems as we learned yesterday of yet another mayoral appointee, Director of Finance Harry E. Black, skipping town without explanation.

News of Black’s defection came by way of John Cranley, mayor of Cincinnati, who had been squiring Black around the Queen City as his choice to become its city manager.

Black even gave an interview to the Cincinnati Enquirer (“Cincinnati is a city on the rise. . . I see tremendous potential”) while we clueless scribes back in Charm City were wondering why he hadn’t taken his customary seat at the Board of Estimates pre-meeting yesterday.

Now we all know about his exciting new job. But asking City Hall for the reasons why he abandoned ship (300 employees and a multi-billion-dollar budget at the start of the new fiscal year) is like asking the ocean to divulge where waves go.

Financial Renaissance?

There had been rumors that Black was preparing to bolt. He never really seemed at home during his 2½ year stay at City Hall, where he succeeded retiring Edward Gallagher, who had spent his career in the finance department.

Black was a nomadic consultant with a problematic resume before he was appointed. He never moved to Baltimore, but rather rented an apartment on North Charles Street and kept his family home in Richmond, Va.

Yesterday afternoon, via a press release from the mayor’s office, we got a summation of his accomplishments: “Baltimore is in the midst of a public financial renaissance. I have been humbled to have been part of this movement and am confident that the City of Baltimore will continue to grow,” Black was quoted as saying.

That’s it. We were left with the glancing allusion to the mayor’s 10-year “Change to Grow” plan and no reason for his attraction to a city much further away from Richmond than Baltimore.

In the press release, Rawlings-Blake chalked up his departure to a job well done. “Our budgets are back in the black [apparently no pun intended], we have made more progress in property tax reduction than any administration in recent history,” she said.

Then casting Black away like flotsam in the ocean, she announced that deputy finance director Henry Raymond (“exceptionally qualified,” “a dedicated public servant”) would become the new department head.

In other words, let’s move on and fuhgeddaboudit. No wonder Raymond was seated in Black’s chair yesterday.

Revolving Door

As far as the former finance director’s place in the parade of officials passing through City Hall, here’s a partial rundown of personnel in city offices since Rawlings-Blake became mayor in 2010.

Chief of Staff. There have been five, including one acting: Sophie Dagenais (2010-11), Peter O’Malley (2011-12), Thomasina Hiers (acting, 2012), Alexander M. Sanchez (2012-14) and Kaliope Parthemos (2014-present).

Mayor’s Office of Information Technology (MOIT). Five directors (three acting): Michael Barocca, Rico Singleton, Robert Minor, Christopher Tonjes and L. Jerome Mullen (current acting director).

Emergency Management and Public Safety. Three deputy chiefs: Christopher Thomaskutty, Yolanda Jiggetts and Robert M. Maloney (current director).

Department of Recreation and Parks. Four directors (two acting): Dwayne B. Thomas, Gregory A. Bayor, Bill Vondrasek and Ernest W. Burkeen Jr. (current director).

Department of Human Resources. Three and counting: Gladys B. Gaskins, S. Yvonne Moore (acting), Ronnie E. Charles, currently unfilled.

Baltimore Development Corporation. M.J. “Jay” Brodie and a nearly complete departure of senior staff under new CEO Brenda McKenzie.

Mayor’s Office of Policy and Communications. Director Ryan O’Doherty and Press Secretary Ian Brennan, who were replaced by Kevin R. Harris and Caron Brace last year.

Some other resignations/early retirements since 2012: Police Chief Frederick H. Bealefeld, Deputy Police Chiefs Anthony Barksdale and John P. Skinner, Fire Chief James Clack, School Chief Andres Alonzo, Director of Public Works Alfred Foxx, Director of Health Oxiris Barbot, Director of Social Services Molly McGrath Tierney, Director of General Services Ted Atwood, Chief of Purchasing Joseph D. Mazza, Director of CitiStats Chad Kenney, Director of Transportation Khalil Zaied (who moved to the mayor’s office), Transportation Chiefs of Staff Jamie Kendrick and William “Billy” Hwang, Deputy Chief of Government Affairs Kimberly Washington (who transferred to Housing), Chief of the Minority and Women’s Business Opportunity Office Shirley Williams, Director of the Mayor’s Office on Criminal Justice Sheryl Goldstein.

By our calculation only one person, Chris Tonjes, has publicly disclosed that he resigned for other than the boilerplate reasons of “new opportunities” and “family” issues.

While being a team player with zipped lips has become the norm, it’s worth noting that the exodus of top bureaucrats does have consequences. It invariably leads to administrative zig-zags and to delays and disarray in vital programs. (Think of those haphazardly closed Rec Centers and our dilapidated Senior Centers.)

Ten-year reports may look nice at gatherings of the U.S. Conference of Mayors, but continuity of good staff is what sets a city on the right course.