For decades the Brooklyn waterfront was filled with manufacturing operations that made mundane products like Chiclets and Ex-Lax. Well, somebody had to make Bon Ami scouring powder and that was Mr. Childs, who built a fabulous mansion in 1900 on Prospect Park West (#53), designed by William Tubby. Rumor has it that Teddy Roosevelt slept there. The AIA Guide to New York City indicates the style is Jacobean.
It is now home of the Ethical Culture Society, which evidently makes it available for receptions, which is the reason I got to explore the interior. The front doors are solid wood resembling something off of a medieval castle, the sun room windows look Tiffany-esque, the staircase banister is made of sword scabbards, the 2nd floor library has mahogany-carved ceiling tiles gazing down on an old book collection, including a crumbling copy of the 11th edition Encyclopædia Britannica.