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years' professorship, who have had a large share in aiding the progress of astronomical knowledge. But astronomy in America is most indebted to him for his papers on the Method of Least Squares, and on the Computations of Special Perturbations. The Method of Least Squares, which originated with Legendre and Gauss, was systematically and successfully applied in Encke's earlier investigations upon the motions of the comet which bears his name, and its inestimable practical value illustrated. His papers on the subject, together with the numerous examples which his applications of it furnish, have placed the method easily within reach of the student, and have enabled many a young mathematician, with no other aid, to proceed with confidence and success in computations which could never have been undertaken otherwise without the instructions of a master. So admirable have been his arrangements of these difficult computations, and so explicit his instructions upon every part of the work, that it may be truly said that the greater part of what has been done since by astronomers anywhere in the correction of orbits of comets or minor planets, or the computation of their perturbations, has been done under Encke’s direction. It was in such work as this that he excelled ; and while he showed no want of ability to take the highest rank in any department of theoretical or practical astronomy, it was as a computist that he was pre-eminent.

Sir John WILLIAM LUBBOCK, Baronet, was born March 26, 1803 ; educated first at Westminster School, then at Trinity College, Cambridge, taking the Bachelor's degree in 1825, the Master's in 1833; was admitted to the Royal Society (of which he was a Vice-President at the time of his death) in 1829; married in 1833; succeeded to the baronetcy in 1840, on the death of his father, the eminent banker, Sir John Lubbock; and transmitted the title to his eldest son, John, also of scientific eminence, by his death at High Elms, Kent, June 20, 1865. Between the time of reading his memoir on the determination of the orbits of comets before the Royal Society in 1829 and the year 1849, he contributed more than forty papers to the Transactions of that body and of other learned societies, on the moon and the tides, the perturbations of planets, the orbits of comets, and other matters of astronomy, terrestrial physics, and pure mathematics.

He holds a conspicuous place among those who have contributed to the perfection of the Lunar Theory. His claims are thus stated by himself in the Transactions of the Royal Astronomical Society for 1860: “ I am confident that a just posterity will give to us (that is, to Plana,

Pontícoulant, and Lubbock, who, in 1846, furnished the means of constructing tables of the moon without any empirical hypothesis] the credit of first bringing the Lunar Tables within the limits of error of observation, and thereby of bringing to perfection the solution of the problem of finding the longitude at sea by means of lunar observations." Of the excellence of the work here referred to, Sir J. Lubbock appears to have first been made aware by its near agreement with the formula from which the American Tables of the Moon were constructed, and the very close agreement of these tables with observation.

Sir William Rowan HAMILTON, Astronomer Royal for Ireland, son of Archibald Hamilton, Esq., of Dublin, was born in that city, August 5, 1805, and early put under the tuition of his uncle, Rev. James Hamilton, curate of Trim, by whom his remarkable taste and ability for learning languages were so much fostered, that by the age of fourteen he had made great progress in thirteen languages besides his own, in which he also showed the finest rhetorical powers. His taste for mathematics (perhaps derived from his mother, whose maiden name was Sarah Hutton, and who was of the family distinguished in that science) was so strong that it led him, with very little aid from tutors, to rapid selfdirected progress. He began geometry at the age of ten, algebra at twelve; at seventeen he bad thoroughly mastered the calculus, and at nineteen, while an undergraduate at Dublin, laid the foundations of a new science ; at the age of twenty-two, not yet having taken his Bachelor's degree, he was made Andrews Professor of Astronomy in his own University ; not because he was an astronomer, nor because his Alma Mater wished him to become an astronomer ; but because she wisely wished to secure the residence of a son of such rare genius and virtue. His mathematical writings consist of a single volume, Lectures on Quaternions, published in 1853, and of numerous contributions to the Transactions of the Royal Irish Academy, from 1828 to 1847; to the Philosophical Magazine, from 1831 to 1861 ; and to the first four volumes of the Cambridge and Dublin Mathematical Journal. These contributions all relate to pure Mathematics or to Analytical Mechanics, - his wealth of metaphysical, poetical, and philological learning and ability never luring him from his chosen walk, and all show a master's hand.

His papers on Optics were the first example of extended investigations into the phenomena of motion abstracted from the idea of force ; and his prediction of conical refraction, having been verified by subse

quent observation, has in it the same sort of moral sublimity as that which attaches to the discovery of Neptune in consequence of Le Verrier's predictions. Led by a remarkable expression of Kant to endeavor to develop the science of pure Time, Hamilton succeeded, first in giving a new and better interpretation to algebra, and afterwards in inventing, or as he modestly says discovering, a quaternion notation for Space, having a generality that enables one to express in a brief equation truths that previously required a volume. We live too near the time of its origin to comprehend its value; but a notation capable of such condensation of expression should be an engine of incalculable power. This Science of Quaternions, first given to the Royal Irish Academy in November, 1843, and published in the Philosophical Magazine in July, 1844, has four kinds of symbols, one for real quantities, and three for imaginary.

In private life he was admired and loved ; the highly poetical imagination which was at the foundation of his geometrical ability showed itself constantly in his conversation. His impulsive, ardent temperament never led him into controversy, but his regard for the rights, the opinions, and wishes of other persons was continually manifesting itself in thoughtful courtesies and kindnesses. He made pure mathematics his study, and metaphysics a favorite relaxation, reaching heights of speculation in both to which few attain ; but he held with devout simplicity to that Christian faith which was the guide and joy of his life. He died September 2, 1865.

The Rev. WILLIAM WHEWELL, D. D., was born at Lancaster, May 24, 1794, and died at the Lodge, Trinity College, Cambridge, March 5, 1866, in consequence of being thrown from his horse some days before. He took the Bachelor's degree at Trinity College in 1816, obtained a Fellowship, was a Tutor for some years, and was appointed to a Professorship of Mineralogy in 1828, holding that office four years, when he resigned. In 1838 he was made Professor of Moral Theology, and resigned the chair in 1855, when he became Vice-Chancellor of the University. He was also appointed Master of Trinity College in 1841, and held that high position at the time of his death.

Dr. Whewell was a man of great and varied learning, handling with ability the most diverse subjects of inquiry; beginning with Reports to the British Association on the Tides, and on the Mathematical Theories of Heat, Magnetism, and Electricity, and with the Bridgewater Treatise on Astronomy, and text-books on Elementary Mechanics ;

then proceeding to a History of the Inductive Sciences, and a Philosophy of the same, afterward called a History of Scientific Ideas; passing thence to the editing of Mackintosh's Introduction to Ethical Philosophy, to volumes of his own upon Morals, and to translations from Plato's Ethical Dialogues ; then to the editing of Richard Jones on Political Economy, and a volume of his own upon that subject, and finally amusing himself with Notes on the Architecture of Churches in France and Germany, writing English Hexameters, and an anonymous book on the Plurality of Worlds.

Dr. Whewell undoubtedly exercised a large influence on public education in England, especially in commending the physical sciences, and giving them an honorable place in the University at Cambridge. His style was singularly clear, and his views of every subject comprehensive, if not marked by peculiar originality. His attachment to the College in which he was educated was earnest, and showed itself not only in his pertinacious resistance of every claim or pretension on the part of others which he thought inconsistent with her dignity, even when claiming rights in behalf of the Crown ; but also by his munificent gift of a large hostel for her students, and of an endowment for its support and enlargement.

The names of HOOKER and LINDLEY, which stood side by side in our botanical section, are naturally associated as those of the two most eminent botanists in Great Britain, — also by the parallel course, and near coincidence in the close, of their lives. Born in the same neighborhood, in youth receiving their education at the same school, and early drawn together by similar predilections, they both devoted themselves with singular energy and perseverance to their chosen pursuit ; exerted for many years, although in somewhat different ways, a paramount influence upon the advancement of botanical science; and died near together in place and time, — the elder at Kew, on the 12th of August last, at the age of eighty-one years ; the younger at Turnham Green, on the first of the ensuing November, at the age of sixty-six years. For a long time they were the two most distinguished teachers in Great Britain, one at a northern, the other at the metropolitan University. They severally conducted two of the principal serial works by which botany contributes to floriculture; and they developed into highest usefulness those two great establishments, the Royal Gardens at Kew, and the Horticultural Society of London. Both wrote and published largely ; — Hooker only upon descriptive botany, in which he

greatly excelled, while Lindley traversed a wider field, and grappled with abstruser problems in every department of the science, always with confidence and facility, but not with unvarying success.

WILLIAM JACKSON HOOKER was born on the 6th of July, 1785, at Norwich, where resided Sir James Edward Smith, the possessor of the Linnæan herbarium, and a leading botanist of the time. It was he, probably, who directed young Hooker's attention to botany; but his fondness for natural history, especially for ornithology, was already developed in the school-boy. Going up to London as a young man, he made the acquaintance of Sir Joseph Banks and of the able botanists he had drawn around him ; in the year 1809 he went to Iceland ; on his return from a successful exploration, the vessel in which he had embarked with all his collections, notes, and drawings, was fired and everything was lost, save the lives of the crew and passengers. In 1811 he published his earliest work, the “ Journal of a Tour in Iceland "; before 1820, he had brought out his monograph of the British Jungermanniea, and the Muscologia Britannica, both illustrated by his own pencil. From 1820 to 1840 he filled, with distinguished success, the chair of the Regius Professorship of Botany at the University of Glasgow ; and he brought out, during these twenty most active years, the greater part of his extensive writings upon Phænogamous Botany, among which we should especially notice his Flora Boreali- Americana, or Botany of British America, founded on the collections of the Arctic explorers, and of his correspondents in Canada and Western North America, including what is now Oregon and Washington Territory.

In the year 1841, when it was determined that the gardens and plant-houses at Kew, then crown domain, should be converted into a great national establishment, Doctor, now Sir William Hooker, was naturally looked to as the proper person to take charge of it. cepted the trust, and, generously supported by the government under every administration, he devoted his energies and rare talents for organization to the creation and development of the conservatories, museums, gardens, and plantations, stocked with the vegetable productions of all lands, which (including also the vast and unrivalled herbarium that he had himself amassed) have, within the short space of a quarter of a century, made Kew the botanical metropolis of the world.

All this he did without much abatement of his activity in botanical investigation and authorship; although of late years restricting his proper studies very much to the Ferns. His most comprehensive work

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