PHYSICAL AND MATHEMATICAL SCIENCES. 157

Copernican astronomy in 1618, than it was honouredby being placed, along with the works of Copernicus , onthe list of books prohibited by the church: he wasconsiderably alarmed at this circumstance, anticipatingdifficulties in the publication of other contemplatedworks ; but it would seem without reason. In the sameyear he became acquainted with the invention of loga-rithms, and even calculated tables of them. He hasput on record a curious notice of the spirit in whichthis invention was received; many mathematiciansappearing to think it derogatory to their dignity to makeuse of tables of results already calculated to theirbands.

In 1620 he was visited by the English ambassadorsir Henry Wootton, who endeavoured to persuade himto settle in England, but he declined, from a desire toprosecute the publication of the Rudolphine tables,which had so long been delayed from want of the ne-cessary funds, promised indeed, repeatedly, from theimperial treasury, but not more readily forthcomingthan his pension. A variety of other causes contributedalso to delay their publication, especially the disturb-ances which accompained the progress of the Reform-ation in Germany. Kepler ’s situation as imperialmathematician alone saved him from the violence ofRomish party : but his library was taken possession ofby the Jesuits .

In 16’27, however, these tables appeared, and con-tained great improvements upon all which had pre-ceded them ; the volume is remarkable in containingthe first suggestion of the method of determining thelongitude from occultations of fixed stars by the moon.

Kepler was now patronised by Albert Wallenstein,duke of Friedland, who valued him only as an astrologer,but was at least a better paymaster than the emperor:in his service Kepler died, November 1630. He lefta mass of unpublished writings, which were examinedby Euler and others, but nothing has been printed; andwe may presume nothing appeared worth publication.