Compiled by P. W. Clarke, S. B., Professor of Physics and Chemistry in the University of Cincinnati. Price, $1.50.

"This work will be found very useful to the merchant, economist, and banker, as the arrangement is highly convenient for reference, and in a form and classification never before presented to the public. It also contains a series of tables, arranged alphabetically, showing the value of each unit as given both in the English and the metric standards. The metric system is used coextensively with the ordinary system, and is a characteristic feature of the book.

"The contents, among other things, contain the following useful and comprehensive tables, viz.: I. Measures of Length, in both the English or American feet or inches, and in French metres. II. Eoad-Measures in English miles and French kilometres. III. Land-Measures. IV. Cubic Measures. V. Liquid Measures. VI. Dry Measures. VII. "Weights, and finally Money. This latter table is one of the most useful and valuable tables probably to be found, giving as it does the standards in dollars, francs, sterling, and marks, and alone is worth the cost of the book." - N. Y. Commercial and Financial Chronicle.

"We commend this carefully-prepared and convenient volume to all persons who wish to acquire information on the subject of which it treats." - Boston Globe.

"The work necessary to the production of this little volume has been judiciously planned and skillfully executed." - Chicago Tribune.

D. Appleton & CO., Publishers, 549 & 551 Broadway, N. Y.

The International Scientific Series.

D. Appleton & Co. have the pleasure of announcing that they have made arrange-ments for publishing, and have recently commenced the issue of, a Series of Popular Monographs, or small works, under the above title, which will embody the results of recent inquiry in the most interesting departments of advancing science.

The character and scope of this series will be best indicated by a reference to the names and subjects included in the subjoined list, from which it will be seen that the cooperation of the most distinguished professors in England, Germany, France, and the United States, has been secured, and negotiations are pending for contributions from other eminent scientific writers.

The works will be issued in New York, London, Paris, Leipsic, Milan, and St Petersburg.

The International Scientific Series is entirely an American project, and was originated and organized by Dr. E. L. Youmans, who has spent much time in Europe, arranging with authors and publishers.