Candela was chosen so that the new definition would precisely match the old definition. Although the candela is now defined in terms of the second (an SI base unit) and the watt (a derived SI unit), the candela remains a base unit of the SI system, by definition. If a source emits a known luminous intensity "I" (in candelas) in a well-defined cone, the total luminous flux "Φ" in lumens is given by where "A" is the "radiation angle" of the lamp—the full vertex angle of the emission cone. For example, a lamp that emits 590 cd with a radiation angle
Rosario Candela the apartment buildings. Candela's greatest work would occur during the latter half of the 1920s, when he designed numerous apartment buildings on the Upper East Side, primarily on Fifth Avenue and Park Avenue, as well as at Sutton Place and other locations. In 1927 and 1928, Candela designed 19 apartment buildings, including 960 Fifth Avenue (at East 77th Street) and 720 Park Avenue (at East 70th Street). He had more commissions in 1929, but the housing boom had begun to slow prior to the stock market crash in October. Of 27 designs that year, only 12 were completed. These included