484 APPENDICES
- Jakob Johann Latib. b. 1872, Jagerndorf, Austria. PhD with W. Wien in
Wiirzburg, November, 1906. Laub published on special relativity as early as 1907
[LI]. At the beginning of 1908, he wrote to Einstein in Bern, asking if he could
work with him [L2]. The resulting collaboration led to two papers on the electro-
dynamics of ponderable media [El, E2].* In 1910, Laub wrote the first major
review article on the experimental basis of special relativity [L3]. He became pro-
fessor of physics in La Plata, Argentina. Later, he joined the Foreign Service of
Argentina and was the Argentinian ambassador to Poland at the time of the Ger-
man invasion in 1939. d. 1962, Fribourg, Switzerland.
- Walter Ritz. b. 1878, Sion, Switzerland. PhD in Goettingen with Voigt,
- Privatdozent in Goettingen from 1908, the year in which he discovered the
combination principle for line spectra. Ritz did not accept special relativity, but
rather believed in the need to give up the notion of a field described by partial
differential equations (see [P2], Sec. 3). Ritz and Einstein published one very brief
joint paper, written in April 1909. I stretch the notion of collaboration by includ-
ing it, since it is a tersely phrased joint communique in which both men state what
they have agreed to differ on. The issue was whether advanced and retarded solu-
tions of the electromagnetic field equations are both admissible types of solutions.
'Ritz considers the restriction to the. .. retarded potentials as one of the roots of
the second law [of thermodynamics], whereas Einstein believes that the irrevers-
ibility rests exclusively on probability grounds' [Rl]. The life of Ritz, a gifted
man, was short and beset with much illness, d. 1909, Goettingen.
- and 4. The Habicht Brothers. Johann Conrad, b. 1876, and Franz Paul,
b. 1884, both in Schaffhausen, Switzerland.** Conrad was one of the members of
the Akademie Olympia in Bern. He obtained a doctorate in mathematics in 1903,
then became a high school teacher, first in Schiers (Graubiinden), then in
Schaffhausen, where he died in 1958. Paul, an engineer, founded a small factory
for the production of electrical and acoustical equipment. He, too, died in
Schaffhausen, in 1948.
As the result of a note on voltage fluctations in a condenser, 'a phenomenon
similar to Brownian motion' [E3], that Einstein wrote in 1907, he became inter-
ested in the possibility of amplifying small voltage differences. He conceived the
idea of using for this purpose a condenser with variable capacity which is charged
at low voltage and maximum capacity, then discharged at a higher voltage and at
minimum capacity into another condenser. This process was to be repeated with
the help of a set of condensers coupled in series. It was his hope that this electro-
static device might be of use for research in radioactivity. In December 1907 Ein-
stein wrote to Conrad that Paul planned to build this 'Maschinchen,' (little
machine), as Einstein always affectionately called it, in his own laboratory. Ein-
*These papers are discussed in [P2], Sees. 33,35.
**Biographical details about Conrad and Paul Habicht and found in [HI] and [R2], respectively. I
am indebted to H. Lieb, Staatsarchivar from Schaffhausen, for directing me to these articles.
