The authors are attempting to clarify the fundamental factors relating to cermet making from the view points of surface and interfacial tensions. The anthors’ previous paper described the surface tensions of pure metals and alloys, and this paper reports experimental results due to effects of dissolved sulphur, oxygen, slenium and tellurium on the surface tension of liquid copper. The results obtained are as follows: The elements of group VIb of the periodic table are highly surface active in liquid copper. The effects of negative elements on the surface tension become more severe with lowering temperature. The degree of adsorption of these negative elements on the liquid copper surface has been calculated, and from the results each adsorption-layer is considered to consist of a monolayer of negatives ions attracting copper ions.