Derek Roberts, Precision Pendulum Clocks: France, Germany, America and recent Advancements, Schiffer, 2004, pp.192-193, figs.35-3a-d; Klaus Erbrich, Präzisionpendeluhren, Callwey, 1978. pp.158-159.
A little known chronometer maker from Hamburg, Johann Diedrich Thies is recorded in the winter of 1880-81 as having entered two chronometers in the trials at the Deutsche Seewarte. His address was given as Neierwall 24 and Posterstrasse 1.
F. Dencker (c.1835-1909) was co-founder of the Chronometer Werke GmbH, Hamburg in 1905 and was its first technical director. For a short period in the 1870s he was in partnership with Theodor Knoblich.
Dencker's regulators are typical Hamburg or Altona style and based on Kessels' design. Erbrich (pp.158-159) illustrates a similarly designed regulator by Knoblich, Altona (No.1808) and Roberts (pp.192-193) shows another, Dencker No.26.