Nothing is known about Jilek's early years in the navy. He first came to prominence when he was chosen to fill the post of personal physician to the
Archduke Ferdinand Maximilian (1832–1867). The occasion may have been Maximilian’s entry into the navy and service aboard in 1851. In October 1852, Jilek was appointed senior doctor at the newly renamed
Imperial and Royal Naval Academy (former Cadet College) at
Trieste and
Pola in
Istria, now in
Croatia, where he also lectured on
oceanography. In March 1856 the Archduke Maximilian, by then Commander in Chief of the Navy, laid the foundation stones for a new
Arsenal and a new Academy building at
Fiume, and in July 1857 Jilek completed the textbook on
oceanography for Academy students, for which he is best known today. Jilek was not an original scientist in this field. He was probably commissioned by the Archduke to prepare a survey of the newly emerging science and that is what, within his limitations, he achieved. Much of the book is given over to general geographical descriptions of the world’s oceans, for which Jilek may have drawn on versions of
Kant’s unpublished lectures on
geography that were produced in the early 19th century. Another source was certainly
Eduard Bobrik’s multi-volume manual of
seamanship,
navigation and oceanography – the first book to use that word in its title. In 1848 the second, revised edition of Bobrik’s manual had included sections on
oceanography,
hydrography, ‘aerography’ and
magnetism. But time and again when Jilek addressed the major physical processes which govern the oceans, the true subject of oceanography, he was obliged to declare that no one yet understood them. However he made a reasonable job of explaining the methods and preliminary results that had recently been presented by
Matthew Fontaine Maury in his
Wind and Current Charts, and had then been enlarged upon in Maury’s masterpiece
The Physical Geography of the Sea, first translated into German in 1856. ==Textbook on oceanography==