U.S. Assistant Secretary of State for African Affairs, G. Mennen Williams described U.S. investment in South Africa as providing "neither the leverage nor the interests that they (the Africans) might suspect." His remarks on U.S. policies and objectives in sub-Saharan Africa were made tonight in national Educational Television's "Great Decisions-1966" series. The program is being broadcast this week on all 104 NET affiliated stations. In an NET interview with international news correspondent David Schoenbrun, the State Department official viewed the South African question as "different" from Rhodesia, which he believes to be "cracking" under economic pressures. Mr. Williams asserted that while our ultimate objective in South Africa is clear, "it's not clear that the same tools would be effective" as they have been in Rhodesia. The South African question is dissimilar to Rhodesia, he maintained, because "Africa is very impatient to see this regime practicing apartheid brought down. The Africans recognize what we want to do but sometimes they feel we're a little slow in using the means at our disposal to bring down that government." To exert economic pressure in South Africa "isn't as easy as one would think," he said, and added, "Our concern in South Africa compared to the rest of Africa is less than half, but South Africa only represents one percent of our foreign investment". On other African affairs, Mr. Williams viewed influence by Communist China as ebbing because "the Africans understand what they're up to and that what they're up to is of no help to them." As for our country's race relations problems, Mr. Williams observed that "by and large the African people recognize that we're on the right track" in trying to solve them. Mr. Williams' appearance marks the fourth in NET's "Great Decisions-1966" series of eight half-hour programs that examine crucial international issues. "Great Decisions-1966" is a 1966 NET and WNDT production. (Description adapted from documents in the NET Microfiche) Great Decisions 1966 consists of 8 half-hour episodes produced in 1966 by WNDT, which were originally shot on videotape.