Thanks to Frank "Steamhead" Wilsey for finding and scanning this for us. He writes, "John Mills was a rather prolific inventor, who most of us know for the Mills boilers (still made today!) and the Mills overhead piping system. But he also came out with his own unique radiator design, which is mentioned in passing in Susan Reed Stifler's book The Beginnings of a Century of Steam and Water Heating. Check out the valve and piping arrangements!"