unreasonably, incensed, and wrote to Halley concerning it in somewhat acrimonious terms. Halley, who seems to have acted throughout a very creditable part, replied by urging that Hooke's conduct had been represented in worse colours than it deserved; whereupon Newton not only expressed his regret for the angry postscript to his last,' but agreed, with the view of composing the dispute,' to insert into the text of his book the following acknowledgment:

'The inverse law of gravity holds in all the celestial motions, as was discovered also independently by my countrymen "Wren, Hooke, and Halley.'"

How far Hooke was pacified by this concession does not appear; but there is evidence that he continued, although in a lower key, to claim ownership in the discovery of gravity. It was, indeed, difficult for him to see with equanimity the great scientific prize of the century, which he had set before him as the crowning glory of his own career, carried off before his eyes by a swifter competitor; and he could not be expected to recognise, what to us is evident enough, that his powers were wholly unequal to the unique achievement of his rival. The intuition of a discovery is one thing, its demonstration another; and while the one excites our interest and curiosity, it is to the other that we justly apportion our unqualified admiration.

Between Hooke and Newton no further intercourse seems at any time to have been set on foot. If Hooke was jealous of Newton, Newton was perhaps somewhat ungenerous towards Hooke. He recognised his merits with reluctance, and acknowledged his inventions only by compulsion. Broils and disquietudes, and the fomentors and originators thereof, were in truth odious to him; and he was at all times disposed to conceal a discovery, rather than risk a controversy. Philo

sophy,' he wrote to Halley,† is such an impertinently litigious 'lady, that a man had as good be engaged in lawsuits as have 'to do with her.' Thus the turmoil raised by Hooke on the appearance of the first part of the Principia' inspired him with so deep a disgust that he seriously contemplated suppressing the remainder; and he could never be induced to publish his work on Optics until the death of his unquiet opponent had secured for it a peaceful reception. But the most significant fact as regards the relations of these two men is

Scholium to the Fourth Proposition in First Book of Principia.' Brewster, Life of Newton,' vol. i. p. 311.

+ Letter of June 20, 1686, Biographia Britannica,' art. Halley.

VOL. CLII. NO. CCCXI.

D

that Newton, who during Hooke's lifetime had never sat at the Council-table of the Royal Society, was, only a few months after his decease, elected both to that position and the still higher one of President, on the same day, November 30, 1703.

per

Not much now remains to be said. Hooke's growing infirmities of mind and body condemned him to isolation; and isolation is the chosen ally of eccentricity. Repeated disappointments had aggravated the inherent moroseness of his disposition; increasing ill-health soured his naturally irritable temper; and the death, in 1687, of his niece, Mrs. Grace Hooke-probably the only person in the world for whom he entertained a sincere attachment-broke the last link uniting him to everyday humanity. Still he pursued his investigations with a feverish energy that age and sickness seemed rather to stimulate than to quell. His jealousy of piratical appropriation increased, with advancing years, almost to a mania; he enveloped his researches in a mysterious reserve; and many of the discoveries which he professed to have made, descended with him into the grave. Amongst these were a means of finding the longitude at sea, and a secret for fecting all kinds of optical instruments. It might be conjectured, from the small size of some telescopes used by him, that this latter invention approached that of achromatism (made by Dollond in the middle of the following century); but, on the other hand, we find him laying it down as an axiom, that increased power could only be obtained by increased focal length; and he is even said to have entertained as a possibility the construction of an instrument 10,000 feet long, which should bring into view the inhabitants of the moon! We cannot, indeed, take his own word for his performances. He was probably not deliberately untruthful; but he was sanguine as well as vain, and apt to discourse largely of results, towards which imagination pointed, but which reason had not yet grasped. The Royal Society, at any rate, so far believed his professions, as to make him, in 1696, a grant for the purpose of completing his researches, and recording his discoveries. The remaining years of his life and his failing physical powers were dedicated, with almost insane zeal, to the task of raising an adequate monument to his experimental genius. Disease was powerless to divert him from his purpose; fatigue never seemed to approach him. Day after day, and night after night, he meditated, experimented, invented. For several years before his death, he was said never to have undressed or gone to bed.

His limbs swelled, his brain reeled, his very eyesight failed; but still he worked, and wrote, and dreamed of immortality. At length a summons came which he was powerless to resist. He died on March 3, 1703, unloved, unlamented, and, at least in his own apprehension, unrecognised. He died, as he had lived, haunted by unfulfilled hopes, and deluded with abortive projects. In the midst of voluntary destitution, he had cherished a magnificent design for the endowment of the Royal Society. But he left no testamentary disposition of his hoarded wealth, which proved as barren after his death as it had been during his life.

Imprisoned in his own egotism, he did not know how to contribute his quota generously to the long day's labour of humanity. He sought to set his trademark on every thought. He would have desired a patent of protection for every experiment. His work was in consequence visited with the curse of sterility. A slave to meum and tuum-in his own words, the great rudder of human affairs'-his peevish reclamations were met with the inexorable Sic vos non vobis of ironical destiny. Of the innumerable inventions which he originated, scarcely one has been associated with his name. His suggestions bore fruit in the hands of others. His ideas were appropriated and perfected by his rivals. His experiments conferred lustre on his successors. By tacit consent, his intellectual inheritance was divided, and his claims ignored. Newton took up the theory of light where he abandoned it, and left him far behind in the momentous search for the law of gravitation. Mayow carried forward the investigations which he had set on foot as to the purpose subserved by the air in respiration.* His method was used by Picard in 1670, with striking success, in his new measurement of the earth. His observations formed the basis upon which Bradley founded, in 1728, his discovery of the aberration of light. That his repeated disappointments and mischances were in any degree attributable to his own deficiencies, naturally did not occur to him. It was simpler and more consolatory to set them down to the prevalent malignity and injustice of mankind. Hence the deepening shade of misanthropy which enveloped in saturnine reserve the later years of his life.

Nevertheless, Hooke was, in spite of conspicuous defects, by no means a bad man. His morals were irreproachable, his diligence was untiring, and his religious sentiments seem

For an interesting account of Mayow's experiments, see Miss Buckley's Short History of Science,' p. 131.

to have been unfeignedly devout. His faults were warpings of the mind, closely dependent, perhaps, on his unfortunate physical constitution. In spirit, as well as in person, Nature had set him somewhat awry. Certainly,' writes Bacon, there ' is a consent between the body and the mind; and where nature erreth in the one, she ventureth in the other. Ubi peccat

in uno, periclitatur in altero.' It was his misfortune that he could neither win sympathy nor inspire pity. His talents earned for him patronage; but his peculiarities repelled friendship. He lived sixty-eight years without attaching to himself a single human being, and died only to make room for his rival. And yet his intellectual qualities did not demand admiration more than his moral failings claimed tenderness. For surely infirmity has been rarely combined with genius in more painful and pitiable guise than in Robert Hooke.

ART. II.-1. Mind in the Lower Animals in Health and Disease. By W. LAUDER LINDSAY, M.D., F.R.S.E., F.L.S. London: 1879.

2. Etudes sur les Facultés mentales des Animaux comparées à celles de l'Homme. Par J. C. HOUZEAU, Membre de l'Académie de Belgique. Mons: 1872.

FEW books are more attractive and popular than those

which treat of the habits and so-called instincts of animals. That the subject must be a fertile one for the enterprise both of investigators and authors, is at once evident from the consideration of the large number of species now known to naturalists. In the book which furnishes the chief suggestions for this article, 914 distinct forms are named as having contributed to the author's generalisations. A comprehensive and really valuable list of 133 works is given as authorities consulted upon this important as well as interesting department of scientific research. Dr. Lauder Lindsay has at any rate chosen a field of investigation which needs no extraneous argument to commend it to the attention of intelligent thinkers and kindlyhearted men; and we therefore proceed to bring the conclusions at which he has arrived, and the method which he has pursued in the prosecution of his labours, under the notice of our readers. We think that some of the facts which he has catalogued and indexed in his voluminous book, and the deductions which he conceives himself to have established, deserve to be presented in a more readable form than that which he has

adopted in his loosely compacted memoir, where, in one instance, sixteen columns and a half are occupied by 328 distinct epithets that he finds to be necessary to express the modifications of language by speechless animals, and where, in numerous cases, page after page is filled by analytical statements which look very much like the terrible tables employed by the modern expositors of the natural system of botany. Whatever may be the advantage of this method of treatment where erratic and puzzling forms of visible structure have to be explained, it must be admitted that it does not constitute attractive reading when broad abstractions have to be dealt with, and when a continuous argument has to be framed. In connexion with this remark it may not be out of place to say that an elaborate index of seventy-three pages is one of the notable features of the work, and that this has been avowedly provided by the author at the cost of several months' close application and labour. It might be wished that a portion of the time which has been devoted to this most copious index had rather been applied to the elaboration of the book itself.

The author of Mind in the Lower Animals in Health and 'Disease' explains that he was first led to the consideration of this subject by an investigation which he undertook twenty years ago to determine how far the diseases of the lower animals may be held to be identical with those of man. The prosecution of this enquiry, of course, comprised a close observation of the healthy manifestation of mind. Dr. Lindsay appears to have been especially qualified for this part of his task by a long experience in the management of the Murray Royal Institution for the Insane, near Perth. He has enjoyed the further advantage of a wide sphere of travel, extending through Iceland, Spain, Italy, Morocco, Egypt, Syria, the United States, Canada, Australia, and New Zealand, and during his wanderings has always had an eye upon the fourhanded, four-footed, winged, and many-legged creatures that he came across. He also appears to have an intimate acquaintance with the principal zoological gardens and menageries of the world, and, besides this, to have devoted his leisure for many years to reading books which relate to the habits of animals, and to making copious notes from them. Upon these several grounds Dr. Lindsay comes before his readers armed with attainments and credentials which entitle him to attentive consideration.

But the author of Mind in the Lower Animals' furthermore assures his readers that he has studied his subject without any