During the second World War Rockside was used as an RAF psychiatric hospital. Many RAF staff affected by the strain of repeated raids on the German city of Cologne found themselves here. Sir John was the commanding officer responsible for running the RAF psychiatric hospital. Rockside Hydropathic Establishment was erected by Mr Charles Rowland, in 1862, and subsequently considerably enlarged. It was situated further up the hill from Smedley's Hydro at a height of 800 feet above the sea level, and could be reached conveniently and comfortably by the cable tram. It later became part of Matlock Teacher Training College, and has now been developed into apartments.