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HISTORY OF PHYSICAL ASTRONOMY.

less fortunate than some of his successors, was struck down by the re-morseless arm of death at the very commencement of his brilliant career.

Having thus been made acquainted with the loss which their countryhad sustained from the premature death of Horroeks, the Royal Society took steps to collect together all the memorials respecting himself andhis friend Crabtree, which might still be in existence, with a view to theirpublication. It was found that much of what Horroeks had written wasirrecoverably lost. Some of his papers, which, for greater security, hadbeen kept in a secret place during the civil wars, were burned by aparty of soldiers who entered his father’s house in quest of plunder.Some were carried to Ireland by his brother, who died there and was nomore heard of. Another portion, which had been deposited in a book-seller’s shop in London, was destroyed during the great fire of I860 . Thetask of editing all the remaining fragments that could be procured wascommitted to Dr. Wallis, who was then Savilian professor of geometryin the University of Oxford. They were finally published at London , inthe year 1072, under the title of “ Jeremise Horroccii Opera Postliuma.”They consist of a defence of the Keplerian astronomy, a selection of lettersfrom Horroeks to Crabtree, astronomical observations of the two friends,and an exposition of the lunar theory of Horroeks by Flamsteed. In tliepreface to the work, Dr. Wallis has mentioned such facts as came to hisknowledge respecting the life of Horroeks, nor has he failed to allude, interms of burning indignation, to tlie apathy with which for more thantwenty years the manuscripts of the youthful astronomer were regardedby his countrymen*. It must be acknowledged, however, that the actof reparation which was finally effected forms a bright episode in theearly history of the Royal Society , and that throughout all the proceedingsconnected with the execution of the task assigned to him, Dr. Wallis ex-hibited a spirit of disinterestedness and zeal which reflects the highesthonour on his character f.

When the early death of Horroeks is considered, his posthumousfragments may be readily supposed to derive their interest rather fromthe indications they afford of what might have been expected from himif a longer term of life had been granted to him, than from any positiveinfluence which they were calculated to exercise on the progress ofphysical science. In the lunar theory, however, he effected an im-provement which would alone suffice to obtain for him an imperishablereputation. His beautiful explanation of the inequality in the moon’slongitude, termed the evection, by means of a libratory motion of theapsides and a variable eccentricity, was the last great step made in tliedevelopment of the laws of the planetary movements previous to theestablishment of the theory'of gravitation by Newton; and there can belittle doubt that it afforded material aid to that philosopher in his expo-sition of the general principles of perturbation as detailed by him in thesixty-sixth proposition of the first book of the “ Principia ” and its famouscorollaries. Horroeks has thus won for himself a place among those great

* “Non possum, inquam, non indignari, pretiosum hoc spectaculum (Venus in SoleVisa) nullo auro redimendum, description, preloque paratum, delituisse per annos inlegrosviginti duo; neminemque interea repertum esse, qui tam beilam patris mortui prolemsusciperet, qui rem tanti ad astronomiam momenti in iueem mitteret, qui nostKe gentisfamoe, vel omnium commodo, eatenus inserviret.”

f The account of the various proceedings connected with this matter will be foundscattered through the first two volumes of Birch's “ History of the Royal Society.”