1. SeeElectric Contacts Handbook, by R. Holm, aided by E. Holm (Springer-Verlag, Berlin, 1957) (to be published); see particularly Chap. 27 where the theory is given with references to pertinent literature.
2. In the theory of contacts the average radius of the conducting spots was labeled “a” and therefore the spots were calledaspots by R. Holm, reference 1, Chap. 2.
3. Melting voltage of copper (gold) is ≈0.43 v.
4. See discussion of Fig. 3(b).
5. Two different grades were used: electrical resistivity 4.5×10−3 and 2×10−3 ohm cm, respectively; thermal conductivity about 0.35 and 0.7 w∕cm deg, respectively.