From Philadelphia Inquirer
Walking through the halls of family-owned Day & Zimmermann's headquarters on Spring Garden Street is like walking through a history lesson, with the company's chairman and chief executive, Harold "Hal" L. Yoh 3d, 54, as the professor.
There's a yellowed photograph of the Gatun lock on the Panama Canal, an early assignment - 1908 - for the contract engineering, technical staffing, and construction management firm that has grown, in part, through acquisition over the decades.