[Alan Douglas]

The schematic (in Rider 1-1) calls it a "B power adjusting lamp" but I think it is really a current limit when the unit is first turned on, and the rectifiers look like short circuits. They need a little time to form. I don't know what the electrolyte was, sodium phosphate perhaps; the early ARRL Handbooks have instructions for making electrolytic rectifiers and mention a couple of possible formulations. At best, these things were messy as the electrolyte tends to creep over the top of the jar.