Lorentz and Poincare. Every paper by Poincare dealing with the principle
of relativity acknowledges Lorentz's pioneering role. In his Goettingen lectures,
Poincare called him one of the 'grands demolisseurs' of Newtonian mechanics (I
wonder if Lorentz would have agreed with that) and referred once again to his
'very ingenious invention' of the idea of a local time.
Conversely, Lorentz had high esteem for Poincare. In his major article of 1904
he acknowledged the stimulus of Poincare's criticism (expressed at the Paris Con-
gress of 1900) to the effect that too many independent hypotheses had been intro-
duced in his earlier work [L7]. Later he wrote to Poincare acknowledging receipt
of 'the important memoir on the dynamics of the electron' [L8]. In Volume 38 of
the Acta Mathematica, devoted in its entirety to appreciations of the late Poincare,
Lorentz gave a detailed analysis of the Palermo paper [L9] in which, incidentally,
an imaginary time coordinate (x 4 = icf) is introduced for the first time. Regarding
Poincare's contributions to the principles of relativity, Lorentz's view is balanced,
as always. In both editions of the Columbia lectures, Poincare appears only in
connection with the stress terms he invented. In a letter to Einstein, Lorentz rem-
inisced about the origins of the special theory: 'I felt the need for a more general
theory, which I tried to develop later [i.e., in 1904] and which you (and to a lesser
extent Poincare) formulated' [L5].
Lorentz and Einstein. As Einstein told me more than once, Lorentz was
to him the most well-rounded and harmonious personality he had met in his entire
life. Einstein's thoughts and feelings about Lorentz were a blend of respect, love,
and awe. 'I admire this man as no other, I would say I love him,' he wrote to
Laub in 1909 [E8]. In a letter to Grossmann, he called Lorentz 'our greatest
colleague' [E9]. To Lorentz himself he wrote, 'You will surely feel that I feel an
unbounded admiration for you' [E10]. In a memorial service held at the Univer-
sity of Leiden shortly after Lorentz's death, Einstein was one of the speakers: 'The
enormous significance of his work consisted therein, that it forms the basis for the
theory of atoms and for the general and special theories of relativity. The special
theory was a more detailed expose of those concepts which are found in Lorentz's
research of 1895'[Ell].
Lorentz's life centered on Arnhem, Leiden, and Haarlem. He was forty-four
years old when he attended his first international physics conference, just across
the Dutch border. At that same age, Einstein had already lived in four countries
and had held four professorships in succession. He, the bird of passage, must at
times have been wistful about the Dutch upper-middle-class stability and serenity
of Lorentz's existence.
Lorentz's esteem for Einstein was extremely high as well. In Chapter 12, I
shall have more to relate about the interactions between these two men at the time
that Lorentz almost got Einstein to accept a permanent position in Holland.
Poincare and Einstein. Why did Poincare not mention Einstein in his
Goettingen lectures? Why is there no paper by Poincare in which Einstein and
relativity are linked? It is inconceivable that Poincare would have studied Ein-
stein's papers of 1905 without understanding them. It is impossible that in 1909
