Redakce Historické demografie přináší pokračování příspěvku Elišky Čáňové, o jejích zkušenostech z historickodemografického výzkumu na Broumovsku. Tentokrát je příspěvek věnován specifickému problému identifikace dětí narozených v jednotlivých rodinách včetně otázce délky meziporodních intervalů.
The work describes briefly the application of the complete solution oí the basic equations of meteoric physics, found in connection with solving the problems of photographic meteor theory, to the construction of theoretical Fresnel characteristics. It is shown how the meteoroid deceleration can be incorporated into concepts of radar physics. The corresponding equations are derived and the possibility of using these Fresnel characteristics for the evaluation of the ablation parameter^and the pre-atmospheric velocity v^ from the registered amplitudes is briefly discussed.
A multi-level calculation of the hydrogen spcctrum by Skumanich and Lites, followed by a two-level rcpresentation of each transition, shows that all the solar Lyman α photons are created in the high chromosphere, above ro^ ≃ 10^2 (ro denote the optical depth at the center of the line). Below this depth the Lyman α line is only fed by
multiple scatterings. The source function decreases, first very slowly and then as ro^ ≃ 10^7. The change in slope occurs at ro^ ≃ 10^5.
We shall present a model for the formation of Lyman α in the chromosphere below the creation region. The hydrogen atom is treated as a two-level atom and the chromosphere as a
semi-infinite medium free of primary sources and illuminated by an isotropic and frequency independent radiation field at ro^ ≃ 10^2. A second order escape probability approximation fields a simple analytical expression which accurately reproduces the behaviour
of the Lyman α source function between ro ≃ 10^2 and 5 10^6 provided the destruction probability is set close to 10“-6. This value agrees very well with that obtained by Skumanich and Lites for the generalized Lyman α destruction probability in the low chromosphere.