Further experimentation and invention by Arnold led to a breakthrough in the late 1770s. He redesigned the compensation balance and developed two designs that showed promise. Known as the "T" and "S" balances, and marked as such in Arnold's 1782 patent (probably because of their appearance), both employed bimetallic strips of brass and steel with weights attached, which changed the radius of gyration with change in temperature. Although these probably needed a lot of adjustment, they appear to have worked well compared to his previous attempts at a compensation balance.