Ilooke maintained, that with an instrument of a span radius, the distances and altitudes of celestial objects could be measured to a second by telescopic sights ; and Ilevelius insisted, in his reply, that with a good eye, and great ex perience, he had obtained the same accuracy in the use of his instruments; and he sent eight distances between stars, for the purpose of being examined by Dr Hooke. Here the controversy was for the present terminated.
In the year 1673, Hevelius published in folio, the first part of his " Machina Celestis, organographiam, sive in strumentor um astronomicorum oinnium quibus auctor sidera hactenus rimatus et dimensus est, accurata deli neatio et descriptio pluribus iconibus Sri incisis illustrata et exornata ; cum aliis quibusdam tam jucundis quam scitu dignis, quim ad mochanicatn opticamque pertinent, anienad vcrsionibus, imprimis de maximorum tuborum construe tione et commodissima directione, necnon nova facillima lentos quasvis ex sectionthus cool expoliendi ratione." Hevelius sent copies of 0)is work le all his friends in Eng land except Dr Hooke ; wno, venge of the affront, published in 1674 his I. Animadversions on the First Part of the Machina Celestis of the honourable, learned, and famous Joannes Hevelius, together with an explication of sonic instruments made by R H." Lund. 4to. This work was characterised by the irritability of its author. It was written with that tone of arrogant superiority, which in jured his own cause, and excited the highest resentment on the part of Hevelius. In the same year, Hevelius sent a letter to the Royal Society, containing a reply to the ob jections of Hook and Flamstead, and appealing to observa tion for the correctness of his opinions. He complained of the "bitterness and boasting" with which he had been at tacked, and requested that the Royal Society would send some eminent astronomer to examine his instruments and method of using them. This reasonable demand was ac ceded to ; and Dr Halley, who held nearly the same opinions as Hooke, was requested to repair to Dantzic. He arrived in that city on the 26th May 1679, and continued with Hevelius till the 18th of July. By means of a good instrument, furnished with telescopic sights, Halley corn pared his own observations with those of Hevelius ; and he particularly attended to the successive observations made upon the same stars by Hevelius, with his large brass sextant. The result of this examination was highly favoura ble to our author. Halley left an attestation, dated July 8.18th, 1679, declaring himself " abundantly satisfied of
the use and certainty of these his instruments and obser vations. And whereas he had before been always doubt ful, that his observations by naked sights might as to some minutes be uncertain, and had therefore wondered why he declined the use of telescopic sights; lie had, partly to gratulate the author's publishing of his observations, and partly to satisfy his own scruples, undertaken that journey, which he now considers as no small happiness, and de. clares himself abundantly pleased with it : and offers him self a voluntary witness of the almost incredible certainty of these instruments, as having seen with his own eyes, not one or two, but a multitude of observations of the fixed stars performed with his great sextant, even by divers ob servers, and by himself sometimes, though less expert therein, being often repeated, most accurately and almost incredibly to agree, and never to differ more than by an inconsiderable part of a minute." In the year 1679, Hcvelius published his " Machinx Celestis Pars Posterior ; rerum Uranicarum observationes, tarn eclipsium luminarium quail occultationum plane tarum et fixarum, necnon altitudinum meridianarum, po larium, solstitiorum et xquinoctiorum, una cum reliquoruni planetarum fixarumque omniunt hactenus cognitarum glo bisque adscriptarum, moue ac pluritnaruni hue usquc ig notarum, observatis, 'rather quoad distantias, altitudines, mericlianas et declinationcs, additis innumcris aliis notatu dignissimis atque ad astronomiam excolendam maxitne spectantibus rebus, plurimortnn annortim sulninis vigiliis indefessoquc 'above ex ipso mthere haustas, permultisque iconibus, auctoris manu aeri incisis, illustrates et exor natas, tribus libris exhibens." Hevelius had fortunately presented about 30 copies of this work to his ftiends; for before it was published, his property of every description was consumed by a dreadful fire, on the 26th September 1679. No fewer than seven "'houses, containing his money, plate, gold, silver, house hold goods, printing houses, great part of his library, the remaining copies of all his printed works, published at his own expence, from the year 1647 to 1679, and particularly his observatory, with all his optical and astronomical in struments, were completely reduced to ashes. Among the articles preserved were the latter part of his Machina Celestis, containing the observations of nearly 50 years, and his New Catalogue of the Fixed Stars.