CHILWA (incorrectly SHIRWA)  , a shallow lake in south-east Africa, S.S.E. of Lake Nyasa, cut by 35° 20' E., and lying between 15° and 15° 35' S . The lake is undergoing a process of desiccation, and in some dry seasons (as in 1879 and 1903) the " open water " is reduced to a number of large pools . Formerly the lake seems to have found an outlet northwards to the Lujenda branch of the Rovuma, but with the sinking of its level it is now separated from the Lujenda by a wooded ridge some 30 to 40 ft. above the surrounding plains . There are four islands, the largest rising 50o ft. above the water . The lake was discovered by David Livingstone in 1859 and was by him called Shirwa, from a mishearing of the native name .