6 DOCUMENT 5 SUMMER 1895 science. Einstein recalls that he studied some theoretical physics before entering the ETH. According to his sister, while preparing for the ETH entrance examination in 1895 he studied Violle 1892-1893. This treatise includes an extensive discussion of wave propagation in elastic media, and markings in Einstein's copy indicate that he read this section. Mention in this essay of topics such as double refraction, the mysterious nature of electric current, and Hertz's experiments indicate that Einstein must have consulted other sources of information on electricity, magnetism, and optics. Hertz's experi- ments on electrodynamic waves stimulated a great deal of public interest in Germany. Starting with his talk in 1889, a number of popular and semi-popular accounts of his results, and of the new views of electromagnetism they supported, were published. It seems likely that Einstein read some of these before writing this essay.  Talmey states that he gave Bernstein 1853-1857 and Büchner 1855 to Einstein (see Talmey 1932, pp. 162, 163), books which espouse a mechanistic outlook. Winteler- Einstein alludes to Talmey and mentions Humboldt 1845-1862 among the books re- commended to Einstein (see MWE, this vol- ume, p. lxii).  See Einstein 1979, p. 14. The Luitpold- Gymnasium did not offer physics until the seventh year (see Appendix B), in the middle of which Einstein left the school.  See MWE, this volume, p. lxiv. Perhaps Einstein knew that the required topics for the ETH entrance examination in physics included "Die Elemente der Lehre von den Aetherschwingungen" (see Appendix C).  A copy of Violle 1892-1893, with a sticker indicating that it was purchased from a book dealer in Milan, is still in Einstein's library. It contains some underlinings and marginal annotations. This textbook covers mechanics, including solids, liquids, and gases, in some detail.  Uber die Beziehungen zwischen Licht und Elektricität (Hertz 1889b) went through nine editions by 1895.  There are striking parallels, for example, between elements of Einstein's essay and cer- tain passages in Sohncke 1891. 5. On the Investigation of the State of the Ether in a Magnetic Field [Summer? 1895] Uber die Untersuchung des Aetherzustandes im magnetischen Felde. Nachfolgende Zeilen sind der erste bescheidene Ausdruck einiger einfacher Gedanken über dies schwierige Thema. Mit schwerem Herzen dränge ich dieselben in einen Aufsatz zusammen, der eher wie ein Programm als wie eine Abhandlung aussieht. Weil es mir aber vollständig an Material fehlte, um AD (Mme. Suzanne Koch, Brussels). Enclosed in the following letter.  Dated by the fact of its enclosure in the following letter, on the assumption that it was written shortly before the latter.