IMG00

Ernst Mach

on -inothcr bronch, op.ics. He had bccn adlecnng data and carrying out confirmatory ezperiments for    when a ncw d,scovcry

trouscd the interest of physicists nil ovcr Europc.

On Novcmbcr 8, .895. Wilhelm Rontgen, a professor at the Urn. eersity of Wiirzburg in Bavaria, discovered what non-German, now eall X rays. Ile submi.ted a paper on the sub,ect to a local physico-mcdical ścięty on Uecember 28. U was mtmethately pubhshed and offprints were sen, to well-known phystetsts antl medtcal men

Frtn/. Exner in Vienna receivcd a letter from Rontgen withm the wcek and on January 4, .896. reported the fmdings to a group of Vi-enm nrofessors.⁶² Ernst Mach, willi his skill in opues, stcreoscopy, and photography, almos, immedia.ely proposed a way for an observer ' “sec” the x-rayed objcct as if it were thrce-d.mensional. A month Inter in February .896 J. M. Eder and Eduard Yalen.a, using Mach’s stereoscopic approach, pubhshed the firs, X-ray atlas Though Maehs work in this arca has ncver been widely recogmzcd, he was m faet the carliest contributor tojUa^Jtercoscopy.⁰

Encouragcd bTih.s I^T^ecess Mach looked forward to morę op. ,ical experiments and finally finishing his book on hght, whicl, in German was first callcd Lichtlehrc and was in.ended .0 companion his work on hcat, WSrmdehre. but even,s gradually oser.ook hm, so that only the first part was cver finished (.9.3) and eyen diat was pubhshed only after his death and with a longer and less fehotous

tiilc.

IX

Ernst Machs only daughter, Carolina Ledercr, oncc recallcd: “Travcl was my /athcr’s passion. He visited Paris, Berlin, and London. In his short summer holidays hc normally went up the Scmmcring [a moun-tain pass south of ViennaJ to Abbazio or Brioni.”⁰* Mach’s wandcrlust was espccially pronounced in 1B98. At the beginning of the ycar, dur-ing his first and only sabbatical, he visitcd Italy. During the summer hc laid plans to visit his son, Ludwig, who had finally rcceived his dc-grcc in medicinc and was now employed in the Zeiss Optical Works in Jena. Ernst Mach remembered the tragic journcy in dctail:

I was in a railway train [July 1898 J when I suddenly obscrvcd, with no consciousncss of anything clsc bcing wrong, that my right arin and leg werc complctcly paralyscd; the paralysi* was intcrinittcnt, so that from

timc to timc I was ablc to movc again in an apparcntly quite nnrmal way. Aftcr somc hours it bccamc continuous and pcrmancnt, and thcrc atso set in an atfcction of the right facial musclc, which prcvcntcd mc from speak* ing exccpt in a Iow tonc and with somc difficulty.⁰⁸

Mach had sufTered a strokc which pcrmancntly paralyzed the right half of his body. His son accompanied him back to Vicnna whcrc Mach endured a long and largcly unsucccssful convalesccncc. His travcling days were ovcr. His mcmory had sufTered and hc could no longcr writc.'⁵⁰ His son would havc to conduct all futurę cxperimcnta* tion. Lccturing was a torturę for bolli Mach and his audicnce and it had to be curtailcd. The flood of publications ran dry. Thiele has listed four Mach books and thrcc articlcs in 1897, one book and two articlcs in 1898, and nothing in 1899.⁶⁷ The ncw ccntury brought hopc and promisc nround the world, but not in the heart of Ernst Mach. He madę his will and prepared for the ncxt strokc and dcath.

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