3 6 6 D O C . 4 8 O P I N I O N T E L E F U N K E N V S . H U T H
1) Vor-Eichbarkeit
á2) Leichtere Isolierbarkeit des Gitterkreises gegenñ den Anodenkreis.
2) Weniger Verstimmbarkeit durch Antennendefekte
3) Schwächeres Auftreten der Oberwellen.
Keiner der behaupteten Vorteile hat irgend etwas zu thun mit dem charakteristi-
schen Merkmal des Kühnpatentes, nämlich Kopplung vom Anoden- und
Gitterkreis durch die Röhrenkapazität. Die erwähnten Vorteile treten stets dann auf,
wenn zwei mehr oder weniger lose miteinander gekoppelte Schwingungskreise
vorhanden sind, unabhängig davon, ob die Koppelung induktiv kapazitiv oder
sonstwie herbeigeführt ist.
Ich kann daher nicht anerkennen, dass die in dem Kühnpatent gegebene Ausfüh-
rungsform einen neuen technischen Vortschritt mit sich bringt.
A. Einstein.
ADS. The manuscript consists of two unnumbered pages. Page numbers are here provided in the mar-
gin in square brackets. The title is in the hand of Ilse Einstein. [35 382].
[1]Dated by the date of Georg Count von Arco’s letter in which he asked Einstein to act as private
expert (see Georg Count von Arco to Einstein, 11 November 1920).
[2]In his letter of 11 November 1920, Georg Count von Arco (1869–1940), one of the directors of
the Gesellschaft für drahtlose Telegraphie m.b.H. (“Telefunken”) and Einstein’s fellow committee
member in the Bund “Neues Vaterland,” requested that Einstein serve as an expert in a lawsuit for
patent infringement. The patent allegedly infringed upon is Deutsches Reichspatent 291604 entitled
“Einrichtung zur Erzeugung elektrischer Schwingungen,” granted on 23 June 1919 to Telefunken. Its
inventor, Alexander Meißner (1883–1958) was an engineer of the Telefunken Company. The infring-
ing patent is Deutsches Reichspatent 310152 entitled “Schaltungsweise zur Schwingungserzeugung
mit Vakuumröhren,” granted to Ludwig Kühn (misspelled in the patent certificate as “Kuhn”), and to
the Erich F. Huth Co.
[3]Revocatory action is filed if the invention’s use is against law or common decency; if it is not
new in the sense that during the hundred years preceding the date of application it had already been
published or used to a degree that other specialists could utilize it; if the invention is the subject of a
patent of an earlier applicant, and, finally, if the substantial part of the application was taken without
consent from another patentee’s descriptions, drawings, models, tools, facilities, or processes.
(Patentgesetz 7. April 1891, §10, Seligsohn 1920, p. 4.)
[4]A compulsory license is issued when the patentee does not give license to an applicant to use the
patent, though it is of public interest.
[5]If an invention is the first general solution of a technical problem, its patent is called a pioneer
patent. In this case, not only the specific construction and its equivalents are protected by the patent,
but also other realizations of the same idea (Seligsohn 1920, p. 130). In his letter to Einstein, Georg
Count von Arco mentioned that in the publications of the Marconi Company, for instance, the patent
was called a “pioneer patent.”
[6]The generation of undamped oscillations by positive feedback is discussed by Barkhausen 1907,
pp. 28–29; the use of electronic tubes for the same purpose was first patented by S. Strauss in Austria
(Austrian Patent 71 340) in 1912, a year before Meißner’s first patent (Zenneck and Rukop 1925, p.
864).
[7]Kühn’s goal was to protect the constancy of the frequency of oscillations from outside influences
on the antenna, at the time a major obstacle to long-distance telegraphy and telephony (higher- energy
radio transmission). For this purpose he substituted the inductive coupling between the anode circuit
and the grid circuit with a capacitive one. For details of the two arrangements, see Zenneck and Rukop
1925, p. 613.