With the help of a diffractometer, Ho�ng T . T . analyzed about a hundred samples of clays from diverse origins : kaolin from alluvions of ancient Quaternary ( Province of B�nh D??ng, Bi�n Ho?) ), the clays of recent alluvions ( different localities between Mekong and �ng Nai river ), or from the weathering of granite, rhyolite and shale of ?L?t area ( Province of L�m ?ng ).
12.
With the help of a diffractometer, Ho�ng T . T . analyzed about a hundred samples of clays from diverse origins : kaolin from alluvions of ancient Quaternary ( Province of B�nh D??ng, Bi�n Ho?) ), the clays of recent alluvions ( different localities between Mekong and �ng Nai river ), or from the weathering of granite, rhyolite and shale of ?L?t area ( Province of L�m ?ng ).
