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HISTORICAL VIEW OF THE
a state of great embarrassment, he was actually sup-ported by the generosity of Tycho, and appointedhis assistant in the office of imperial mathematician tothe emperor Rodolph. He was engaged with Tychoin the formation of new astronomical tables, which, itwould appear, the emperor patronised almost entirelywith a view to the purposes of astrology; and whichwere to be brought out on a magnificent scale, under thetitle of the “ Rudolphine Tables.” Tycho’s formerassistant, Lomberg (or Longomontanus ), had retiredinto Denmark on an appointment to an astronomicalprofessorship: on Kepler , therefore, devolved the task ofdiscussing Tycho’s observations, and more especiallythose on the planet Mars . This work was, however,interrupted by the death of Tycho; on which Kepler succeeded to the principal situation which he had filled.He now prosecuted his observations ; and in particularhad the opportunity of examining the new star whichappeared in 1604 in Serpentarius . At this time, also,he entered largely into discussions on the pretensions ofastrology, in which he appears to have believed in amodified sense; but it is rather difficult to make outprecisely what his opinions were, from the extraordi-nary style in which the statement of them is couched.
His appointment in the emperor’s service appears tohave been attended with the constant vexation of adifficulty in getting his pension paid. This interruptedthe publication of the “Rudolphine Tables;” butmeanwhile he produced a treatise on Comets , and his“ Paralipomena in Vitellionem,” in 1604. This workcontains many original views, though mixed up withmuch visionary speculation. It bears unquestionablemarks of genius ; but, like many of his other writings,much of it is excessively tedious, from the detail inwhich he gives the account of the whole train of hisinvestigations. It contains two principal researches ofinterest: one relating to the structure of the eye, theother to the law of refraction.