work to ornithology that had up to that time been seen; and S. F. Baird, who first (1858), in conjunction with J. Cassin and G. N. Lawrence, revised the entire system of North American birds, and very recently (1874), in union with T. Brewer and R. Ridgway, has published the first three volumes of a work which surpasses all others in accuracy of description, philosophical breadth of views, and comparative valuation of characters. Lastly may be mentioned Birds of the Northwest: a Hand-Book of the Ornithology of the Region drained by the Missouri River and its Tributaries, by Elliott Coues (1874). While these general works were in course of publication, many minor works and articles were printed on the general subject, on the species of limited regions, and on the modifications of structure and color induced by geographical and climatic causes, etc. The most successful students of the causes of geographical variation have been Baird, Allen, and Ridgway. The reptiles and amphibians, although extremely unlike in structure, superficially resemble each other so closely as to have been always confounded together and studied in common under the general head of herpetology. This has been a less cultivated branch than others, but several eminent naturalists have elucidated our species, and more than either of the preceding classes has the present owed its advancement to natives. J. E. Holbrook, of South Carolina, published, in 1843, a North American Herpetology, in five volumes, which was then unsurpassed by any similar production in Europe. S. F. Baird, Charles Girard, Edward Hallowell, and Louis Agassiz have done eminent service on different groups, and more recently E. D. Cope has revised the entire herpetological fauna in connection with the general system of reptiles and amphibians. The students of fishes have been more numerous. In the last century but little was known of these inhabitants of our waters, and even that little was inexact. In 1814 S. L. Mitchill, a man of great eminence in his day, published a valuable though crude memoir on the fishes of New York; in 1839 D. H. Storer reported on the fishes of Massachusetts; in 1842 J. E. De Kay published an important work on the fishes of New York; and in 1855, and again in 1860, J. E. Holbrook commenced an illustrated work on the Icthyology of South Carolina, but suspended it with the first volume. The fishes of the extreme West and of the Pacific coast, almost absolutely unknown till 1854, were in that and in immediately succeeding years described by Agassiz, Girard, Ayres, etc. Among other cultivators of the science may be mentioned Kirtland, Baird, Brevoort, Gill, Putnam, Abbott, Cope, Bliss, Goode, Garman, Milner, Yarrow, and Jordan. The invertebrates for purposes of study fall into two groups-the air-breathing insects and the marine forms. The insects soon attracted attention, and the various groups engaged active students. Say (1818 et seq.), Fitch, Packard, Walsh, and Riley have described species of almost every group. The coleoptera have been studied by Melsheimer, J. Leconte, Haldemaun, and above all by J. L. Leconte and Horn; the lepidoptera have had numerous students-Morris, Clemens, Edwards, Packard, Scudder, Grote, and many others; the hymenoptera, or groups thereof, have been examined by Norton, Saussure, etc.; the orthoptera have been investigated by Scudder, Thomas, and Sydney Smith; the neuroptera by Hagen; the hemiptera by Uhler; and the diptera have engaged the attention of Loew and Osten-Sacken. The myriopods have been described by H. Wood, as have also the pedipalp arachnoids. The marine invertebrates were almost wholly neglected till Say, in 1818, commenced his investigations, and for some years worked upon several of the groups, describing our most common crustaceans, shells, and other forms. A. A. Gould, in a work on the invertebrata of Massachusetts, made evident the paucity of our knowledge of all except the shells; and a few years afterward (1851) W. Stimpson, then a very young man, commenced his researches, which added very largely to our information. In recent years the work thus commenced has been worthily continued by the two Agassizes, H. J. Clarke, A. E. Verrill, S. Smith, O. Harger, and others. The mollusks, on account of the beauty of their shells and the ease of preserving them, have, like the birds, been favorite subjects for amateur students, and this has directly and indirectly accelerated our acquaintance with the species. The laborers have been very many. It must suffice to name, besides the general students of invertebrates previously referred to, Isaac Lea, A. A. Gould, Amos and William G. Binney, Thomas Bland, Edward S. Morse, William H. Dall, and George W. Tryon. These have studied, some all the groups, others the land or fresh-water shells, others the anatomy, and still others have especially considered the problems connected with their geographical distribution. PALEONTOLOGY. In no department of natural history has progress been so distinctly marked, or the revelations so interesting and unexpected, as in that which takes cognizance of the former life of our globe. The science of paleontology, as this branch has been named, had absolutely no existence or name when known, and the mammalian faunas of past times, pliocene, miocene, and eocene, have become tolerably well known. Among the most interesting of the types discovered are many forming "connecting links" between the existing ruminants (cattle, deer, etc.) and hog-like animals first made known by Leidy; others lessening the interval between the proboscidians and ordinary pachyderm ungulates, discovered by Cope and Marsh; others demonstrating the line of descent of the horses of the present day, elucidated by Marsh; and still others establishing the former existence in North America of animals most nearly related among living forms to the lemurs of Madagascar, as Marsh was the first to clearly demonstrate. Numerous other almost equally important discoveries have been made, illustrating the structure and range in time and biological generalizations for almost every group of vertebrates; but this is not the place to recount them. the United States became a nation. Fossils analogous deposits were subsequently made were classified by Linnæus not with animals or plants, but with minerals. Their nature was then in doubt. By some they were supposed to be sports of nature, or abortive simulacra of what the Deity destined afterward to create. By the best informed and orthodox they were believed to be witnesses of the Noachian deluge. In a number of cases their nature was, indeed, recognized, but by none was it definitely realized that most fossils were the remains of forms that are no longer living. Although this truth became apparent to several at nearly the same time, Cuvier was the first to render it clear and popular by the restoration of numerous fossil remains of the skeletons of mammals found in the tertiary deposits of the neighborhood of Paris. These were so demonstrably different from any animals that were known in a living state, and the improbability of their having remained undiscovered if still living was so extreme, that conviction of the truth necessarily struck every one who considered the evidence. The clew thus gained, although at first imperfectly held, was soon firmly grasped and followed by many interested students, and the present assured superstructure has been the reward of their zeal. In this country the science engaged the attention of many, and Say, Lesueur, De Kay, and Greene were among the earliest. ton, Conrad, Lea, Hall, Meek, Gabb, White, and Whitfield, besides many others, have described and identified the fossil invertebrates. Hall has especially published a noble work on the fossils of the paleozoic formations of New York. Meek has done more than any one else to illustrate the fossils of the carboniferous and mesozoic beds of the West; and Conrad has excelled in knowledge of and labors on the species of the tertiary rocks. Lea and Gabb have efficiently supplemented the works of the last two. GEOLOGY. Geology is almost entirely the child of the present century. Its foundations were chiefly laid by Werner, of Freyberg (after 1775), and his school in the clear recognition of the nature and the relations of rocks to each other, and their distribution; by Mor-Hutton, of Edinburgh (1788), in the comprehension of the origin and natural causes of the strata and rocks, and in the limitation of cataclysmal agencies; and by William Smith, an English surveyor (1790), and Cuvier (1808), in a general perception of the restriction of fossils to definite horizons, and the value of those fossils in determining the relative age of the strata in which they were imbedded. In each case, indeed, these had been to some extent anticipated in their discoveries, but their ideas were clear and positive, while their predecessors failed to recognize the full significance of the facts in question. The age had also become ripe to apply the truths thus perceived. The vertebrates have received attention from another class of scientists. For their comprehension an exact knowledge of the details of comparative osteology was requisite, and the students have, therefore, been comparatively few. De Kay, Harlan, Godman, Hays, Cooper, Redfield, Warren, and Wyman simultaneously or successively touched the subject, but the great labors have been accomplished by Leidy, Cope, and Marsh. It had by some become supposed that America would furnish no deposits of fossil bones such as had been discovered in Europe, but in 1846 and 1847 Dr. Hiram A. Prout, of St. Louis, and in 1847 Dr. Leidy, published communications on remains found in the Mauvaise Terres of the then Territory of Nebraska, and those deposits have since been a fruitful source of new discoveries. Nothing worthy of mention was done for the geology of North America till William Maclure (a pupil of Werner), in 1806, came to this country and undertook a geological survey, traveling in the prosecution of this self-imposed task from our Northern border to the Gulf of Mexico. He was engaged on it for about three years, and in 1809 published the first geological map, and a commentary thereon in a special memoir. As was to be expected, he adopted the Wernerian system of nomenclature, and having been unable to apply paleontological evidence, his work exhibited little more than certain points in structural geology. Lardner Vanuxem (1828) first availed successfully of paleontology for the determination of Other regions containing the age of several of our formations and In every department of geology America has exhibited efficient works. Stratigraphical, chronological, dynamical, and mineralogical geologies have each had its votaries, and so numerous have they been that the simple mention of their names is precluded. their approximate synchronism with Euro- | auspices. Also productive of similar work pean beds. The natural history survey of have been, or are, the surveys of the 40th the State of New York, commenced in 1836, parallel, and the Territories west of the brought together a great mass of facts, and 100th meridian, already referred to under by the concert of the several geologists and the head of general natural history. paleontologists, but especially guided by the judgment of Vanuxem and James Hall, a classification of the rocks on sound paleontological principles was instituted, which, as since perfected by Hall, has been adopted as the standard of reference for the paleozoic rocks of the United States and British North America. Henry D. Rogers, in his final report on the geology of Pennsylvania (1858), made evident the skill with which he had disentangled the complications of the geological structure of the Alleghany system. F.B. Meek during a long series of years has acted as the universally accepted arbiter for the determination of the age of the groups of rocks in the far West. Meanwhile the details of the geology of the various geographical sections and States engaged the attention of many laborers, and one after the other almost every State instituted a geological survey, and many of them undertook at intervals two or more. In the order of first publication of results they are as follows: 1824, North Carolina; 1826, South Carolina; 1832, Massachusetts; 1834, Maryland; 1835, Tennessee; 1836, New Jersey, New York, Ohio, Pennsylvania, Virginia; 1:37, Connecticut, Maine; 1838, Indiana, Michigan; 1839, Delaware, Kentucky; 1840, Rhode Island; 1841, New Hampshire; 1845, Vermont; 1850, Alabama; 1853, California, Illinois; 1854, Mississippi, Wisconsin; 1855, Missouri; 1858, Arkansas, Iowa; 1859, Texas; 1865, Kansas; 1866, Minnesota; 1869, Louisiana; 1875, Georgia. Such are the principal incidents of progress in the knowledge of the natural history of our land. Many important discoveries have not been even alluded to, and the limitations of space preclude notice of the advance of anthropological science and the general propositions and principles of biology to which American naturalists have contributed. THEO. GILL. The general government also from time to time instituted special geological surveys, independent of the exploring parties mentioned in the first part of this article. In 1834 and 1835 G. W. Featherstonhaugh investigated the elevated country between the Missouri and Red rivers and the Wisconsin Territory. At various times D. D. Owen conducted surveys in several States and Territories of the Northwest, publishing the chief results in 1844, 1848, and 1852. In 1869 the persistent solicitations of F. V. Hayden, already well known as a field geologist and collector, secured a geological survey of Nebraska, under the auspices of the Land-office, a bureau of the Interior Department. For two years this was prosecuted, and the wedge having been thus driven, the survey was continued, and, organized under a more ample scope and with enlarged designs, is continued to the present time. A number of eminent men have availed themselves of the means of investigation and publication presented to them by the survey, and consequently a number of valuable publications have appeared under its SMITHSONIAN INSTITUTION, WASHINGTON, D. C. OUTSIDE. BY CARL SPENCER. WITHIN, the hearth is warm and light, Looks in, beholding paradise. Scarce can the happy hearts believe How glad the fires of every eve. Or stand too far to feel the bliss. Ah, life! what songs are sung outside For alms of voiceless souls within! What halo crowns the bliss denied! What glory flies from hands that win! Joy mocks her still at one remove. With songs around the Father's hearth, With but the exile strains of earth! The heart goes wandering up and down; Grows fast and fair her love's renown. 'Thy silence broods to warm her songs. THE GOTHIC ARCHITECTURE. BY JOHN J. STEVENSON. HE influence of the Gothic style has been so marked on our architecture generally that it may not be out of place to devote a few pages of Harper's Monthly to an explanation of its development. This will turn out to be the shortest way of explaining its principles, and enabling us to judge how far it is suited for modern domestic requirements. beginning of the tenth century, they began to recover their freedom. When with rising civilization churches or monasteries and towns began to be built, architecture had to begin at the beginning again. Roman buildings remained every where, but no one knew how they had been constructed. These in their new buildings the people copied as well as they could, making up for miserable construction by lining them inside with marble and gaudy painting. Although England and France developed each its own forms of Gothic architecture, similar advances being made independently in both countries about the same time, as is When they began to build churches, they the case at present in astronomy and other attempted a reproduction of the old basilsciences, the style was imported into En-icas, or halls for the administration of jusgland already somewhat advanced. Its first tice (as had been already done in Italy), the appearance was in France, and there, from form of which churches still retain, a large the more logical character of the people, less central nave or vessel, with an aisle or pastolerant of compromise than we are, its de- sage along each side, half the width and velopment can best be traced. It sprang height of the nave, opening into it through from an imitation of the buildings which a range of pillars supporting round arches, the Romans, during several centuries of oc- above which was a range of windows called cupation, with their faculty of giving their a clear-story, lighting the central nave. At conquered provinces not only their language, first, as they were unable, from poverty and but their manners, had left every where want of skill, to reproduce the Roman vaultthroughout Gaul, in their own round-arch-ing, the roofs were wooden. But churches ed style, palaces, baths, aqueducts, bridges, in those days, like theatres now, were albasilicas, and villas or country-houses like ways being burned, and attempts were made villages, consisting of straggling agglomer- to make the roofs as well as walls of incomations of buildings one story high, connect-bustible material. In the south of France ed by covered colonnades, for country residence and the cultivation of the soil. After a century or two of pillaging excursions the German barbarians settled in the land. About the middle of the sixth century the Franks had occupied the whole country except part of Languedoc, held by the Visigoths; the east, held by the Burgundians; and Brittany, which was not conquered. By these conquests they lost the social organization they had brought with them. Ceasing to be a conquering army under a single head, the habit which Cæsar and Tacitus had observed in their ancestors arose again among them, each tribe dwelling apart, isolated from its neighbors by tracts of waste land. Military chiefs became landed proprietors, heads of little independent sovereignties uncontrolled by the central power, their companions in arms, almost their equals before, being now their dependents. With their love of plunder and fighting, when there were no more villages and towns to pillage, they took to fighting among themselves, and it was some centuries before even the rude national unity of feudalism became a fact as well as an idea. In this anarchy the monasteries were the only refuge of civilization, preserving some traditions of Roman art and order, organizing needful trades into guilds-a system afterward adopted in the towns when, in the this was attempted—without the use of wood-by a plain wagon vault, as it is called, from being like the cover of a long wagon stretched on half hoops. This vault they covered with solid masonry in the ordinary form of a roof (Fig. 1). But for this a round arch was very unsuitable; a pointed one Α Λ Fig. 1. Fig. 2. saved weight on the apex, and had less thrust (Fig. 2). And wherever they got the idea, whether out of their own heads, which is not impossible, or through Venice from the East, where the pointed arch seems to have been used continually since the time of the Pyramids and Nineveh, it was for vaulting almost immediately adopted. But the arches opening between nave and aisles and those of the windows were still round. In another way the pointed arch was found advantageous in construction. Attempts, again from a desire for fire-proof construction, were made to build domes. Gothic had once a chance of becoming a domical style of architecture. If a square is supported on four arches, and carries a dome (Fig. 3, plan), the bottom of the dome being quite inside the angle pillars, must be supported from them by four spherical triangles (a a, Figs. 3, 4, and 5) whose points rest each on one of the pillars, and whose bases, turned uppermost, form together the lowest ring of the dome. These triangles resting on their points, their tops a quarter of a circle, their sides each half of one of the supporting arches, are called pendentives, from their hanging, as it were, in the air. Now if the arches whose curves their sides follow are pointed (Fig. 5), the pendentive will be longer than if the arches were round, and, the projection being the same, will not slope so steeply forward; while, if the arches are round, the top part of these pendentives must project actually level, and thin away to nothing, and consequently a dome is more easily placed on pointed arches than on round. Fig. 5. north of France, in what was called the Royal Domain, comprising Paris, Rheims, Amiens, etc.* At first, their churches being large, the builders confined their fire-proof constructions to the side aisles, for they were unable to vault over the wider central portion; nor could they afford to lose the range of windows, or clear-story, as it is called, which lighted this central part, by Neither of these styles of Gothic was ever raising the side aisles so as to make them Fig. 6. developed. In them the windows and openings always remained round. The domical style, with the means at the command of the builders, was suited only for small churches, and could not serve the needs of the great towns of the North. The style with wagon vaults was suited only for the South, for churches so constructed were difficult to light. To form an abutment for the massive central vault the lower side aisles had to be carried up to its springing, thus abolishing the clear-story, and preventing any light getting into the central nave except from the side aisles, leaving the central vaults dark caverns (Fig. 6). Then the roofs all stone did not do. Water got through their upper surface, as will happen, and filtered through the solid roof in devious courses, the place where it appeared on the inside being no indication of the position of the leak outside, so that it was found necessary, especially when the vaulting became more intricate in form, to make it merely an inner ceiling, protected outside by a simple wooden framed roof. Gothic, as we know it, developed in the abutments to a wagon vault. For this difficulty they found in Roman work a solution which enabled them to vault the central nave and yet preserve the clear-story. By dividing the continuous wagon vault of the nave into square compartments, and running another vault across each compartment, so that the two vaults intersected, as the Romans had done, they concentrated the thrust on the four angles of the compartment, where it was abutted, at first ineffectually by tall buttresses, but with larger experience completely, being carried down to the ground by half an arch above the aisle roofs, to which is given the name of flying buttress. At the same time an arched space was left clear in each compartment of the nave above the aisle roof, in which windows could be opened. These improvements are shown in Fig. 7. This form of |