dedicated and outstanding Editors for Exploration Geophysics. In the most recent era our five Editors have been: Don Emerson (1984–93); John Denham (1994–99); Shanti Rajagopalan (2000–01); Lindsay Thomas (2001–08) and Mark Lackie (2009–19). Congratulations on this outstanding milestone and thank you to all of our past and present Bulletin and Exploration Geophysics Editors and our many Associate Editors! In addition my personal congratulations on the publication of Vol. 50 Issue 1, to Mark Lackie, our Editor for more than 10 years. As we move closer to our 50th Anniversary, there will be much more to say on 50 years of Australia’s exploration geophysics journal. Thirty three years in the making, our dedicated Preview Editor and contributors have delivered the 200th issue – a fantastic milestone for our Society! Preview was first published in January 1986 as the ASEG Newsletter Preview No.1, edited by Peter Elliot, who led the early development years of the Preview Newsletter. Preview began to morph from a newsletter to a magazine with the first colour pages appearing in Preview with much fanfare in December 1992, under the editorship of Anita Heath (1988– 1992) and then Geoff Pettifer (1992–96). Anita and Geoff were followed by Mike Shalley (1996–97), Henk Van Paridon (1997–99), and then a decade of further progress and a long period of dedicated editorship by David Denham (1999–09). The readership of Preview expanded further under the guidance of Ann-Marie Anderson-Mayes (2009–12) and John Theodoridis (2012–14). Lisa Worrall, our current Preview Editor, continues to receive the highest level of acknowledgement for her outstanding editorship of Preview. Very recently I was cc’ed into some email praise to our Editor from David Pratt, who said “I really appreciate the effort that you and your associate editors put into the production of this high quality newsletter. I really look forward to reading Preview as it gives me some idea of what is happening in the industry between conferences. Like many of my generation, I really appreciate the high quality, printed version. Your dedicated efforts have made this a must-read newsletter which makes us all feel like we are part of a community that cares about each other and where we are going.” On behalf of the ASEG Federal Executive and our Membership, congratulations and thank you to all of our past and present Preview Editors, Associate Editors and our contributors over the years, and a further BIG thank you to Lisa Worrall for a great Preview Issue 200! Henderson byte: Nikola Tesla In Preview 194, it was explained that there are 29 SI units, all of which are used in geophysics, and 19 of which use the names of scientists. One such name is NikolaTesla, a tesla (T) being the unit of magnetic flux density or magnetic induction (informally; magnetic field strength), first named in 1960. In magnetic exploration the nanoTelsa (nT) is more common. Because Tesla was such a great inventor, the Wikipedia biography on Tesla, https://en.wikipedia.org/wiki/Nikola_Tesla runs to 42 pages (whereas the number of pages in the same format for Isaac Newton is 31, and for many other inventors is less than ten). The page also lists 27 books and journals and four documentary videos about Tesla. He is also distinctive in having a flourishing Memorial Society devoted to him. Nikola Tesla was born in 1856 in what was Serbia, now Croatia, and emigrated to New York in 1884 - where he died a poor man in 1943. His greatest invention was an alternating-current system, which was much more efficient than the direct- current system promoted by Thomas Edison at around the same time. Tesla received funding for his AC systems from George Washington, and they became central to many present-day systems used throughout the world in industry and household appliances. Tesla also patented the basic system of radio in 1896. His published schematic diagrams describing all the basic elements of the radio transmitter were later used by Marconi. He combined radio technology with a remote control device, to demonstrate remote wireless operations, which he called“teleautomation”or, as we would call it today, robotic control. In 1896 he made X-rays of a man, one year after Roentgen announced their discovery. Among his other discoveries are the fluorescent light and laser. He foresaw interplanetary communications and satellites. Very much more information on Nikola Tesla is available in his biography, which is available from the Tesla Memorial Society of New York (www.teslasociety.com/biography.htm). The Society also holds the“Tesla Collection”of 1700 newspaper and periodical articles written about him from 1886 to 1920. There is even an FBI file on Tesla running to 156 pages and containing letters signed by J Edgar Hoover. For the last ten years of his life Tesla lived, and died, in the New Yorker Hotel, occupying rooms 3327 and 3328. Both of these rooms now have a plaque on the wall with a short biography of the great man. Roger Henderson rogah@tpg.com.au ASEG news President’s piece 3 PREVIEW JUNE 2019 Ted Tyne ASEG President president@aseg.org.au