The theme is unswerving determination by ten great explorers who faced unknown terrors in savage places. Originally aired on BBC-TV, these narratives will be telecast in the States as a ten-part series, beginning in January. Each story is moving, in fact crawly if you stress the horror: Antarctic gales, Brazilian jaguars, Congo cannibals, crusted swamps. But each episode takes its tone less from the physical feel of place than from the spirit of the individual explorer. Thus Mary Kingsley, who opened West Africa to trade and settling, sees the wilds through the eyes of a melancholy spinster; she died at 37, apparently a virgin, commenting, ""(I) now and then sit and warm myself at the fires of real human beings."" Standouts are the lively and amused Baron von Humboldt who catalogued plants and flowers in Central and South America, and Charles M. Doughty (Arabia Deserta), a clumsy bumbler who subjected himself to total humiliation and endless maltreatment by Arabs so that he could write of areas no white man had seen. Other explorers include Roald Amundsen, James Cook, Jedediah Smith, and Pizarro. Swift, fresh, and intelligent.