Electrical contact resistance between two tungsten rods, which are placed crosswise and pressed together with a pressure from 10 to 100g, is measured over the temperature range from room temperature down to the boiling point of liquid nitrogen. The experiment is performed with the specimen which have been subjected to three kinds of surface treatments, namely, mechanical polishing, electrolytic polishing and etching. It is found that the contact resistance depends on the contact pressure and varies linearly with temperatures, pursuant to the kind of surface treatment. From the experimental results, the contact resistance is considered as consisting of two parts, namely, the convergence resistance and the transition resistance which is independent of temperature. By using these relations, the contact area and distance are estimated under certain assumptions. Some explanatory discussion is also attempted on the relationship between contact resistance and surface condition on the basis of the experimental results
