Mathematics-Such as, superficial and cubic measurement; geometrical division of plantations; line measurement; leveling with level board and instrument.

Mensuration The art of measuring the contents of wood in given divisions of land, by hypsometrical calculation, in order to deter-. mine the total contents of large forest districts.

Physics in General-Meteorology, dew, frost, mist, clouds, rain, snow, hail; the electrical and optical phenomena in the atmosphere, auroras, falling stars, meteors, ignis fatuus.

Chemistry in General-The constituents of the soil, and the elements it should embrace; and how to distinguish the varieties of soil; analysis of the substances found in vegetation, and the mode of absorption.

Mineralogy in General-Concise description of minerals and rocky formations composing the earth's surface.

Botany in General The distinctive qualities of plants; a description of the most important forest trees.

Zoology in General-Wild animals and game.

These preliminary studies lead to

Forest Culture-Tree nurture; process of seeding, gathering, selection and preservation of seed; planting and seed beds; cuttings and layers; wood cutting, trimming, pruning; high and low forest land; process of cutting and clearing; usual times for cutting timber, and the limited age of each kind; rearing and cultivating various

trees.

Protection of Woodlands-Against man, wild animals, insects, poisonous plants; natural casualties, as cold, heat, wind, snow, water, fire, vapor.

Utilization of the Forest-A description of the various kinds of wood; their weight, heat product, elasticity, tenacity, cleaving and absorbing qualities, texture and durability; liability to open and crack; adaptation of various woods to soil and climate; the diseases of wood, and the various forms in which they attack trees; collecting and assorting trees for market; transportation, and its various modes by man and beast and its own gravitation, and by water; conversion to charcoal; application of the various woods; working and application of the different grades of building timber; individual uses of wood, such as extraction of turpentine, litter, small gleaned wood; forest pasture, turf and quarries; arrangements and plan of the forest.

Surveying and Drafts-Time for the full development of the forest, and reckoning of space allowed for estimated contents of trees when arrived at maturity; table of age by years, indicating when the various timbers should be felled; plans for felling wood; plans for cultivation; plans for roads.

Book-keeping-General examination and review of forest plantations; forestal estimates and valuation of contents.

Forest Organization-Direction, government, finance, department, legal enactments, forest police, game laws; care and distribution of wild game.

As professional forestry in this country will not be called for until the necessity of restoring the forest will popularize the study of sylviculture, and reduce it to a system, which will be introduced first into agricultural, and next, perhaps, partially into general education, Ebermayer's complete course will not be needed by the American student. The elementary step into the science is already indicated by the proceedings of our agricultural colleges in experimentally rearing trees, watching their growth, and receiving instruction in botanical laws that have a bearing upon arboreal vegetation, and in witnessing from year to year the progress of nature's own rules. Centuries spent in observation and the accumulation of experience have been the cost of that matured scientific knowledge of dendrology that distinguishes the European savant.

In the passing operations of nature in her arborescent forms he will find how the various species of trees are adapted to soil, latitude, climate and barometrical position, and his close observations will lead him into the application of mineralogy to the subject he has entered upon.

In the exploration of our native forests he should not confine his investigations to the forestal riches of his own State, but he should pursue his researches into States of different latitudes, where new discoveries will be made, and the most striking contrasts will present themselves, when the low and insignificant growths of the arid soil are exchanged for the lofty hemlocks of four hundred years' maturity, standing in their dark humid soil. In this direct appeal to nature, much that he would have to learn from European writers would thus be dispensed with. Here in this country, and in this epoch, the operations of nature, of which we are the cotemporary witnesses, will ever be our surest guide. Not the least pleasing fea

ture of the new science will be found in tracing out the laws of association and congenialities of trees we have already dwelt upon; their affinity to each other, and the provisions made for them, from their earliest creation, for mutual protection. Here amid our own primeval forests the school for this species of information is ready to receive its disciples, and easy instruction is held out by visible nature as she exercises her invisible laws before us.

We believe that forestry itself will prove not only a useful, but most fascinating study, and where the whole philosophy of nature as displayed in the realms of flora is combined with the practical and professional department of the subject, a large share of American thought and attention will be enlisted in its behalf.

J. H.

NEW BOOKS.

MANUAL OF THE VERTEBRATES OF THE NORTHERN UNITED STATES, including the district east of the Mississippi river, and north of North Carolina and Tennessee, exclusive of Marine Species; by David Starr Jordan, M. S., M. D., Professor of Natural History in N. W. C. University, and in Indiana State Medical College. Chicago, Jansen, McClurg & Co., 1876.

A work like the present one has doubtless long been in the minds of students of the North American vertebrata as a necessity to be supplied at the earliest possible moment. Nothing like proper instruction in this department of Natural Science has been possible to our colleges and other schools, on account of the lack of books of the class to which the present work belongs. We, therefore, hail Prof. Jordan's book as the first of the series of popular works which shall be available for instruction in one of the most important regions of human knowledge.

The author of this book presents it as his first important contribution to Natural History; for although known as an author, he here first offers some original views on questions of classification. But the work is necessarily in great part a compilation, and as such requires a knowledge of an extensive and in some divisions scattered literature. It is evident that the successful accomplishment of such a task requires all the knowledge possessed by the special student, as well as the industry of the compiler.

The qualities of the work are positive, both good and bad. The energy of the author has overcome many obstacles both in the field and closet; and its defects are often due to bad exemplars in our scientific literature, quite as much as to inexperience.

In general it may be said that the author displays an extensive knowledge of the species of North American vertebrata, and a full acquaintance with the literature of the subject, while its defects are in the definitions employed in the classification, and the mode of presentation of the characters of groups above the species. As a compendious catalogue it can be highly recommended, and in some of the divisions the diagnoses of the species are well drawn up; in others, as in some of the birds and mammals, they are too short to serve a useful purpose. But the effort of the author to present contrasts in each case is obvious, and merits praise; for nothing is more difficult to the student than to be told that species No. 1 has a long bill and No. 2 long toes, and then to be expected to point out the difference between them.

The higher divisions adopted in the classification, are those expressive of the latest results of comparative anatomy, and the work is in so far superior to all those which have preceded it in the same field. But the anatomical characters themselves are very lightly touched, or omitted altogether, which is a serious defect. A greater defect is the frequent introduction into the diagnoses of families, of characters which have no such value, but which only belong to lower groups.

When, however, we come to the keys by which the genera aredistinguished, the almost universal employment of specific characters instead of generic characters is simply exasperating. Size, color and proportions are constantly employed empirically in definition of the genera, where good structural characters exist, and are generally pointed out in the books and essays consulted by the author. It is however to be here remembered that this is not entirely true of ornithology, where a number of family names are employed by authors of authority which do not represent any definite idea, their characters if existing, not having been yet pointed out. It is far better to disuse such names, since they form no part of a science, and are only stumbling-blocks to the student. Such, for example, are the Sylvicolidae, Tanagridae, Saxicolidae among birds, and Etheostomidae, Labracidae and Ceutrachidae among fishes. The presentation of insufficient or erroneous characters is, however, even more disadvanf tageous, as in the case of the tortoises, where our author has un-suspectingly followed Agassiz, and has accordingly omitted all their real definitions. The author in fact states in more than one place that certain characters (which are the only reliable ones) are "not adapted for his purpose." What would be thought of the botanical hand-book, in which characters of stamens, ovaries and placenta were omitted from the definitions as not adapted for the purpose? Our author's position in this matter explains why he is thrown back on specific characters instead. This is to be observed in cases where some of the true characters are included, as for instance in the Cyprinidae. The characters of the pharyngeal teeth which come first, or nearly so, in discrimination of the genera, are subordinated to

points of color and form, which are specific only; the former not visible excepting at certain times of the year.

The evil of this matter is in brief, that where it teaches anything it teaches error. Generally the species characters are not practicably available in the endeavor to discover the reason why a species is to besought in such and such a genus. But if, on the other hand, they produce the impression on the mind of the student that they are the true characters of the genus, he or she will have made little progress in zoology. But in the case of those who are ambitious to perfect such a system (?) it will give occasion for the creation of an infinitude of names, which will confound the student and use up some valuable lives which may be occupied in endeavoring to understand or catalogue them. That the author has had some trouble of this kind is obvious, especially in the case of the genera of Pericidae allied to Etheostoma. Here the utter want of characterization by supposed authorities is noticed under the name Nothonotus, which as Prof. Jordan remarks, should with Catonotus be referred to Poecilichthys.

This brings us to the question of nomenclature. Our author has made an effort to inform himself fully in this direction, and has been largely successful. One of the features of the book is the attempt to bring into use the names of Rafinesque. Our opinion as to the propriety of this measure will depend on our ideas as to the carrying out of the law of priority. In the critic's view, names, to have authority, must represent something. Hence all catalogues are useless lumber. If a species be characterized, and the genus not, the specie's name only has authority-although the genus's name might be used just as any erroneous generic reference is used, until some one establishes the genus by characterizing it under any name that he sees fit. When the genus is erroneously characterized, no empirical mode of identifying that genus should be allowed, but it should be presumed that the diagnosis is correct, until the author modifies it, or the type specimen from which his diagnosis was taken, can be found and used as evidence. Where it is only a question of probabilities as to what the type specimen of the author was or is, real evidence is wanting, and the name should be, for the time being, disused. This is necessary for the obvious reason that individuals of species may at some time be found which really agree with the description supposed to be erroneous. It is not safe to presume that we have seen all that was under the eye of a previous writer, unless we have seen his types. Some have carried this view so far as to hold that it is only necessary to have specimens in a museum, and distribute duplicates, to create a nomenclature; all of which is impossible, and is fully met by the usual rule that names without diagnoses have no authority.

As regards Rafinesque, he is to be preferred to some modern authors, in that he gave diagnoses for his genera and species; but cannot claim a high position, in that these diagnoses were often