men as to the insanity of Clark, which ended in a respite being procured. We can hardly imagine the possibility of this man being brought to trial, still less of his trial being proceeded with, and the poor man being condemned, had the opinion of any medical man of experience been taken as to his sanity, or capability of defending himself. If medical testimony is too often conflicting, it is perhaps as much the fault of the lawyers as the doctors, and of law itself as of medical science. The improved state of medical science ought surely to render the descriptions of disease more and more accurate and true to nature. If our laws must retain the definitions and distinctions by which insanity and idiocy were limited and distinguished a hundred years ago, it can hardly be expected that lawyers and doctors can ever agree on the subject. The one must necessarily describe disease as he finds it in nature, the other describes it as he finds it defined by Blackstone, Hume, or the Twelve Judges; and they will get further and further apart in their notions, until a new code of legislation shall be made, founded upon the truths of modern observation and knowledge, and the law be cleared of those obscurities which make doctors differ and lawyers disagree. Sir G. C. Lewis on the Astronomy of the Ancients. 485 ART. VIII.-An Historical Survey of the Astronomy of the Ancients. By the Right Hon. Sir GEORGE CORNEWALL LEWIS. London, 1862. Pp. 528. Or all the physical sciences, astronomy is the most generally interesting in its early history, as well as in its future progress. The mechanism of the heavens, as displayed in the sun, moon, and stars, is the first problem which human reason labours to solve. The great luminary which lights and heats us, and gives life and beauty to fruit and flower, would, even if it appeared fixed in space, be the object of an intense and rational curiosity. But this curiosity is greatly enhanced when we follow him in his daily and annual movements. The ruler of day and night, the measurer of labour and rest, and the arbiter of times and seasons, the Sun could not fail to be associated with every thought and action of life; and when not worshipped as a god, must have been contemplated with gratitude and wonder. His daily disappearance beneath the horizon, whether of land or of sea, and his re-appearance undimmed on the following morning, must have aided the primitive astronomer in forming a more correct idea of the Earth on which he lived. A circular plane, immoveable in space, as it appeared to the eye, could not long be regarded as the figure of the Earth. The nightly course of the Sun proved that the circular plane must have had an under as well as an upper side, unless its pedestal had been perforated with a tunnel to allow the luminary to pass. But as soon as it was observed that the Sun rose and set at different points of the horizon, and that at every point of the circle a star rose or set, and consequently passed beneath the circular plane, it must have been placed beyond a doubt, that the Earth was a solid body suspended in space. In grouping the stars into constellations, or simply marking the individuals of the groups, the primitive astronomer must have noticed that a certain portion of the firmament revolved round a point which had always the same position among the stars. The motions and phases of the Moon,-the eclipses of these luminaries,-the direct and retrograde motion of the planets among the stars,-the occultations of the stars and planets. by the Moon, and the phenomena of comets,-must have been universally observed, and made the subject of anxious and interesting speculation. When we contrast these celestial phenomena taking place apparently on the surface of the firmament, or at the same distance from the Earth, fixed in space, with the present acknow ledged system of the universe, with the solar system advancing in space, with the more extended system of the comets, and with the sidereal system of stars and nebulæ,-we can hardly exaggerate the interest with which we trace the steps by which such grand truths have been established. At what results the earliest astronomers arrived, in what manner the true motions, and distances, and form of the heavenly bodies were deduced from their apparent motions, and distances, and forms, are topics of curious inquiry, which have exercised the talents of very distinguished writers. The history of ancient astronomy, which presents many points of historical and physical interest, has been composed under very different influences. It may be written by the philosopher, in illustration of those mental processes by which profound and complex truths have been wrested from obscure data and imperfect observation, or established in opposition to individual prejudices and national superstition. It may be written by the astronomer in enthusiastic admiration of the phenomena which he described, and of the laws of nature which these phenomena establish; or it may be written by the scholar, whose critical skill and knowledge of ancient languages enable him to elaborate the opinions of individual astronomers, and ascertain their precise import as historical rather than as physical truths. From these different points of view, various histories of astronomy have been written and published. That of Weidler, which appeared in 1741, is merely an account of astronomers of all ages and countries, with a list of their works. The History of Astronomy, by Bailly, published in 1775, 1779, and 1782, is a popular and fascinating work, distinguished by its eloquence, but marred by groundless speculations respecting the antiquity of the Indian and Chinese astronomy. The History of Astronomy, by George Costard, Vicar of Twickenham, published in 1767, is little more than a collection of propositions and problems, in which astronomy is applied to geography, history, and chronology, interspersed with brief sketches of the history of the science. The next work on the History of Astronomy is the elegant sketch of the science by La Place, appended to his Systeme du Monde, and entitled Precis de l'Histoire l'Astronomie, in five chapters, the three first of which relate to the astronomy of the ancients. It is in the great work, however, of Delambre, on Ancient Mediæval and Modern Astronomy, that the future historians of the science will find a mine of information collected and analysed by one of the most learned and accomplished astronomers of the present age. These various works did not supply the want which was felt in England for a popular history of astronomy. Mr Narrien, of the Royal Military College, Sandhurst, was therefore, led to compose his Various Histories of Astronomy. 487 Historical Account of the Origin and Progress of Astronomy, forming an octavo volume of 24 chapters. Mr Narrien regards his work as a convenient introduction to a treatise either on Descriptive or Physical Astronomy, and as holding an intermediate place with respect to the voluminous histories of MM. Bailly and Delambre.' The work of Sir George Lewis, to which we are about to direct the attention of our readers, is written with a different object from that of any preceding historian. The histories of Delambre, as he justly observes, were composed by an astronomer principally for the use of astronomers, and require a knowledge of modern mathematical astronomy. But as astronomy is conversant with subjects of daily observation and speculation, such as Chronology and the Kalendar, its history has numerous points of contact with the general history of mankind, and concerns questions which interest a wider class than professed astronomers, for whose benefit the existing histories have been mainly composed.' It therefore appeared to the author, 'that an attempt might be advantageously made to treat the history of ancient astronomy, without exclusive reference to physical science, and without any pretension on his part to that proficient and comprehensive knowledge of modern mathematical astronomy which some of his predecessors in the treatment of this subject have possessed.' Like several of his predecessors, Sir George begins with the astronomy of the Greeks, as affording a firm footing to the historian, and afterwards proceeds to determine how far they derived their knowledge from foreign nations. With this object in view, he divides his work into eight chapters, as follows:Chap. I. Primitive Astronomy of the Greeks and Romans. II. Philosophical Astronomy of the Greeks from the time of Thales to that of Democritus. III. Scientific Astronomy of the Greeks from Plato to Eratosthenes. 33 IV. Scientific Astronomy of the Greeks and Romans V. Astronomy of the Babylonians and Egyptians. During the long period of five centuries which elapsed between Homer and Herodotus (born 384 B.C.), the Earth was regarded as a circular plane, surrounded by the heavens, which was a solid hemispherical vault. The ocean was supposed to flow round this plane as a horizon, and the stars to rise from and again set on the circle of water; and those who did not accept this rude idea from daily observing the diurnal reappearance of the heavenly bodies, regarded the lower hemisphere as a cold and dark abode, communicating with the upper Earth only through the mouths of caves. It is difficult to believe that during so long a period of time such gross ignorance could have prevailed. However limited was the extent of the habitable earth in those early days, the positive fact that every advance upon its surface in any given direction disclosed a new circular plane, overpassing that which preceded it, ought to have established it as a truth, that the Earth was at least a rounded mass, disclosing more and more of its rotundity as the traveller advanced over its surface. The certainty, too, that the Earth must have had an under side, either solid or fluid, or both, should have led to the conclusion that the under would resemble the upper side, since every new advance on the upper side, showing its rotundity, proved that the part of the under side not previously discovered was rounded. We have no doubt, therefore, that the roundness of the Earth would have been discovered by actual observation, had not erroneous opinions been propagated by the poetry and mythology of the times. The necessity of obtaining certain measures of time led to an accurate observation of the movements of the Sun and Moon. The alternate recurrence of day and night, as shown in the Sun's diurnal course, must have soon determined the length of a day, the fundamental unit in the measure of time. The study of the Sun's annual course, marked by the differences in the seasons, though of greater difficulty, must have led to the discovery of the Sun's annual course, or to the length of the year, and also to the determination of the equinoctial and solstitial points. As many of the most interesting occupations of civil life depended upon the seasons, the division of the year into four parts was indicated by the wants of man, as well as by the aspects of nature. It is singular, however, that the Egyptians and the ancient Germans had only three seasons, spring, summer, and winter; and it is curious, as remarked by Sir George Lewis, that in our own language three of the seasons are denoted by AngloSaxon words, whereas the word autumn is borrowed from the Latin. Sir George accounts for this by remarking that autumn is a less definite season; but we can hardly admit that the ripening of the fruits of the Earth, and the beautiful decay and fall of the leaf, are not as characteristic of a fourth season of the year as the torpor of winter, the heat of summer, or the revival of nature in spring. Beside the recurrence of the seasons,' as our author observes, there were certain special and local phenomena which returned at annual periods;' the Etesian winds, |