I used to own a Braun Hobby flash, with wet cells as you describe. It was indeed a very powerful flash; I often used it to take yearbook pictures of high school basketball games in the late 1960's. One interesting design aspect is that the flash tube is offset somewhat within the covering glass envelope. This allows you to turn the reflector one way or the other around the tube, thereby changing the nodal point of the flash vis a vis the reflector, thereby throwing either a wide-angle or more narrow-beam flash. And you could pull the reflector entirely and go bare bulb -- which makes for very interesting photos when used in a room, so you get reflected light from all directions.