David Clayton-Thomas, the Canadian singer and songwriter whose soulful voice was ubiquitous on American radio in the late 1960s and early ‘70s as lead singer of the brass-driven group Blood, Sweat & Tears, has died, according to his publicist. No cause of death was cited except that he died peacefully at a Toronto hospital on Wednesday evening; he was 84. Clayton-Thomas wrote “Spinning Wheel,” the group’s most well-known original composition, which reached No. 2 on the Billboard Hot 100 in 1969, one of three songs by the band to reach that mark in that year; “When I Die” and the...