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Ernst Mach

and finish thc many tasks hc had promiscd his fathcr that hc would accomplish or at lcast try to accomplish. Lowic publishcd thc following notc in thc magazinc Science:

Dr. I.udwig Mach, thc only surviving son of thc latc Ernst Mach, is threatened by economic pressure with thc prospcct of having to abandon thc housc and laboratorics in which hc has for ycars cndcavorcd to com-plctc his fathcr's physical rcscarchcs. The premises contain a complctc archivc with Ernst Mach’s notebooks and diarics, on the basis of which Dr. Ludwig Mach had hoped to prcparc a mcmoir of his father’s lifc. Eviction from thc valuablc but hcavily mortgaged property would mcan thc dcstruction of all thc materiał asscmblcd. 3000 to 4000 marks would stavc off thc immediate difficulty. Since thc casc is urgent, rcmittanccs of thosc interested should hc addrcsscd dircctly to Dr. Ludwig Mach, Vatcrstcttcn bci Miinchcn Landstrasse 61, Germany.⁹⁴

The campaign, which somewhat ironically includcd a financial con-tribution from Albert Einstein himsclf, was succcssful and so cncour-aged Mach’s son that hc sent to Professor Lowic a prospectus of all Ernst Machs writings that hc intendcd to finish and have publishcd. As thc document is uniquc and as accuracy has somc valuc, I quotc it at length in German.⁹'

Ncuziwcróffcntlichcndc Schriftcn

1.    Grundziige der physikalischcn Optik Band II.

2.    Neuausgabc von ‘ Kultur und Mechanik” (in ctwa 3-4 fachem Umfange das bisherigen und mit maschincntcchnischcm Anliang.)

3.    Im Zusammenhang mit dcm 2. Band der "Optik” sollcn Abhandlungcn iiber dic Lichtgcschwindigkcit und den Ablauf der Lichtcmission zur Vcroffentlichung kommen. Ein Tcil dicsscr Arbcitcn stcht mit der VolIcndung cincr jahrclangcn Vcrsuchsrcihc unmittclbar vor dcm Abschluss. Ober sekundare Intcrfcrcnzcn u.s.w.

4.    Ein Biindchcn tcchnologischcr Untcrsuchungcn mit Betrachtungcn iiber dic Konstitution der Materie. Zum tcil cnthalt dicsc Schrift cbcnfalls cinc Rcihe optischer Untcrsuchungcn von Ernst und Ludwig Mach.

5.    Ein Bandchen soziologischcr Studicn.

6.    Ein Bandchen cnthaltcnd cinc illustricrtc biographische Lebenskizze iiber Ernst Mach von Ludwig Mach.

It is unlikely anyone will cvcr know how close Machs son camc to finishing his task beforc the catastrophe took place. Ludwig Mach had set up a 500-metcr-Iong serics of “light lines” in thc forest and open country around his housc in order to carry out his expcriments on thc naturc of light.*⁶ Hc hoped that the isolation of his housc and ap-paratus would keep clcctrical intcrfcrcncc to a minimum. During thc

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Did Mach FinaJly Acccpi Einstein's Theory oj Relatirity?

winter of 194.4, hovvevcr, thc German army strung high-tension wires ihrough thc aica wlicrc thc cxpcriments wcrc conducted. /Ul protests shattered against spccific military instructions and thc desperate nccds of the failing German war effort.'⁷ Ernst Mach had spccificd that if the light expcrimcnts provcd fruitlcss, then thc sccond half of his Optics should be destroyed.'”" According to Frau Anna Karma Mach, Ludwig*s wifc sińce 1940, her scvcnty-six-year-old husband in a fit of despair and unrclievcd wecping destroyed nil thc remaining unpublished articlcs and books by Ernst Mach.⁰⁰ Ludwig Mach had dcdicated him-sclf to aiding his fathcr in any and cvcry possiblc manner, but on thc question of light and relativity hc had failed. Hc died on August 22, 1951.¹⁰⁰

Joseph Petzoldt had tried to find a theorctical way to rcplacc thc principle of the constant vclocity of light. Ernst and Ludwig Mach sought an expcrimcntal determination of thc naturc of light. Einstein defined its characteristics; Mach wanted to know what light actually was.

If Ludwig Mach, or anyonc elsc, could havc cxperimcntally proved Einstein s principle of the constant velocity of light in a vacuum, then Ernst Mach would surely havc acccpted at least that aspect of Ein-stciids theory of rclatWity, but theorctical physics aims at Ycrification rather than proof. Hugo Dingler argucd that cmpirical verification could ncvcr constitutc proof.¹⁰¹ If Mach acccptcd Dinglcr’$ point of vicw, then perhaps there was ncither a theorctical nor experimental way to persuade Mach to accept the above principle and Einseein’s theory of relativity.

On the Inrger question of Mach’s influence on Einstein, one can hardly avoid thc condusion that in spite of the cxtent of that influence, therc is something grotesąuc in considcring Ernst Mach, the leading opponent of theorctical physics, as thc "forerunner” of Albert Einstein, thc most succcssful of all rcccnt proponents of theorctical physics.