International Scientific Series.

D. Appleton & Co. have the pleasure of announcing that they have made arrangements 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 coöperation 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 spent the greater part of a year in Europe, arranging with authors and publishers. The forthcoming volumes are as follows:

Prof. Lommel (University of Erlangen), Optics. (In press.)

Rev. M. J. Berkeley, M.A., F.L.S., and M. Cooke, M.A., LL. D., Fungi; their Nature, Influences, and Uses. (In press.)

Prof. W. Kingdon Clifford, M.A., The First Principles of the Exact Sciences explained to the non-mathematical.