In the visible part of the spectrum, the methods to solve astrophysical problems by laboratory experiments are well known. Electric arcs or shockwaves allow the production of plasmas of known parameters, from which measurements of oscillator strengths, of line broadening effects, and of line shifts are possible. However, there was a difficulty to introduce elements into laboratory light sources which have no volatile compounds. This was particularly difficult for the metals. This difficulty was overcome only recently by burning the electric arc in argon gas containing a few percent of chlorine. When this gas mixture is led over heated metal, some metal-chloride is formed and fed into the arc. In this way, even a very small amount of metal can be investigated, so that the resonance lines of the metals are optically thin. As an example I would like to recall that during the past year Professor Richter at Kiel has succeeded in a redetermination of the absolute oscillator strengths of iron lines, which has allowed to correct the abundance of iron in the Sun’s atmosphere. The abundance turned out to be ten times larger than assumed hitherto, leading to a new conception of the conditions in the photosphere (Kock and Richter, 1968; Garz and Kock, 1969; Garz et al., 1969a, b; Baschek et al., 1970). With this abundance, there is no difference in composition between the solar photosphere, the corona and meteorites. The method used for iron was applied to a number of other elements. The abundance of nickel is of special interest. The ratio of iron to nickel is again the same in the photosphere, in the corona, and in meteorites, being 1:1.25±0.15 (see Figure 1).