If an electromagnetic field can be represented by a pure electric wave (E-wave or TM wave, transverse magnetic field) or a pure magnetic wave (H-wave or TE wave, transverse electric field), then as a boundry value problem, when the operating frequency tends to zero, the electromagnetic field will be re-duced to an electrostatic or a magnetostatic field, respectively. Hence the solution of such an electromagnetic problem can easily be obtained from that of the corresponding static problem, because there exists an one-to-one correspondence between the terms of the series solution of the electromagnetic problem and those of the series solution of the static problem, and therefore we can obtain one series from the other, using the rales of determining the integration constants in the unknown series outlined in this paper.We point out two possibilities of the existense of pure electric waves and pure magnetic waves; one in coordinate systems satisfying eq. (3) and other conditions discussed in this paper and the, other in problems where some forms of symmetry exist so that the system of Maxwell's equations can be broken into two independent groups, which we also call respectively electric waves and magnetic wavea.By means of the proposed-method some complicated boundry value problems can be solved with ease as we have done here for the problem of the excitation of waveguides by a dipole from the known solution of the corresponding static problem. Since there is a rich accumulation of electrostatic and magnetostatic problems so the method proposed here should be valuable in solving field problem and should be studied further.

The problem of diffraction by a narrow slit in an infinitely thin and perfectly conducting plane is solved by a method developed in the accompanied paper, from the known solution of the corresponding magnetostatic problem.

The formation energy of vacancy is calculated from, the surface tension of solid. It is found that the theoretical values of vacancy formation energy of metals agree with its experimental values, the vacancy formation energies of metals are directly proportional to its energies of self-diffusion and melting points, and the ratio of the energy of vacancy formation to the energy of self-diffusion, determined by one of the above proportional relations, is 0.43. Besides that, the vacancy formation energy is also a periodic function of atomic number.

In this paper the relationships between small-signal h-parameters and elements of the natural equivalent circuit of the common emitter configuration of junction transistors are studied. From experimental results of h-parameters of two typieal alloyed PNP transistors (one 2N104 and one п-6 transistor) the relationship of h-parameters and elements of natural equivalent circuit vs operating frequency and d. c. operating condition (d.c. emitter current and d.e. collector voltage) are evaluated. Results thus obtained ace then compared with results obtained from analysis based on calculations using physical constants of the transistor. The explanation of the behavior of the reverse open-circuit voltage amplification factor, μ_{bc}, of the common emitter circuit is given in detail. Characteristics of μ_{bc} and properties of h_{22} (the output admittance with input open) are correlated. This paper gives complete information about h-parameters and natural equivalent circuit of two transistors, serving as an important reference for both device men and research workers on transistor circuits.