Page:Popular Science Monthly Volume 3.djvu/407

Rh, required, that should give the latest scientific information respecting foods, so clearly and simply written as to be understood by common people, and that should combine fulness of statement with compactness of form and a moderate price. Dr. Smith has realized these difficult conditions in a very remarkable degree in the volume now prepared. Adopting a classification that is recommended by its simplicity, he goes over the whole field and describes the properties, composition, preparations, and adaptations of all the alimentary substances now employed by civilized man. In his preface, the author remarks: "Largely-increased commercial intercourse with distant countries, associated with a marked improvement in the purchasing power of the masses of the people, and the rapid increase of wealth generally, have attracted public attention to the subject of foods and dietaries in an unusual degree, so that not only is there a greater importation of foreign productions than formerly, but new foods, or preparations of foods, are produced almost daily, some of which are specially fitted for certain classes of persons, as children, while others are of general use. Hence our food-supplies, whether natural or prepared, offer increased variety of flavor, if not of nutritive qualities, and foods which were formerly restricted to the few are now commonly found on the tables of the many.

"Scientific research in every civilized nation has also diligently busied itself in the elucidation of the subject, and our knowledge has been increased in reference to the chemical composition, preparation, and physiological effects of food.

"With so many causes of change since the issue of my work on 'Practical Dietary,' it seemed desirable to produce another which should embrace all the generally known and some less known foods, and contain the latest scientific knowledge respecting them, while at the same time the subject should be treated in a popular manner.

"It was originally intended to include both foods and diets in one work, but the subject has now become so large that it was found necessary to limit the present volume to foods alone, and to reserve the subject of diets and dietaries for a future occasion."

The amount of information that Dr. Smith has contrived to compress into this little volume is quite surprising; it seems, indeed, to have the completeness of a regular cyclopædia of the subject. Besides giving the pith of what is known of the whole range of aliments proper, simple and compound, he includes those outlying groups of bodies which, whether or not they be properly foods, are habitually taken into the system, and have great physiological importance. The properties of water, of air, of wines and spirituous liquors, are well summed up in their relations to the living organism. The volume contains many illustrations and valuable tables, with full-page diagrams, representing graphically the effects of various alimentary agents upon the system in different times and circumstances. Dr. Smith's work will be a standard manual upon the important subject of foods.

is a book written, as the introduction informs us, "for use at the United States Naval Academy." It is, then, intended to be used by young pupils as a first book, and must be judged by the rules which apply to the ordinary text-book: that is to say, it must be, before all things, clear, eminently accurate, and it must be calculated to develop in the student a habit of exactness; and, since it is a textbook of so practical a subject as navigation, it must be a book of reference which the graduated midshipman can safely use. These are the tests which any one, who writes a book on navigation and nautical astronomy, must attempt to satisfy, and which, it seems, should be easily satisfied, since the subject is an old one, and since such a writer has many works of able predecessors to consult.

These conditions this volume in no wise fulfilsfulfills [sic]. Indeed, its author tells us, in the early portions of his book, that, in the work of interpolating from the "Nautical Almanac," formulæ have been given to meet each