Concerning the question of how H. A. Lorentz first had arrived at the Lorentz transformation (i.e. concerning his 'testamony', as E4mmacro calls it), I found now a relevant remark in K. F. Schaffner, Space and time in Lorentz, Poincaré and Einstein: divergent approaches to the discovery and development of the special theory of relativity"; in: Machamer, P. K., and Turnbull, R. G. (eds.) (1976) Motion and Time, Space and Matter, Interrelations in the History of the Philosophy of Science, Ohio State University Press, Chapter Seventeen, p. 465: "Lorentz thought that Einstein had arrived at experimental results that were in essential agreement with those that he, Lorentz, had obtained, and that Einstein had 'simply postulated' what he had 'deduced, with some difficulty and not altogether satisfactorily, from the fundamental equations of the electromagnetic field.' "  Schaffner's citation is taken from p. 230  of Lorentz's The Theory of the Electrons'' of 1909. How is it possible to "deduce" a correct result in a "not altogether satisfactory" manner without knowing the final result in advance?