those on the physical properties of water contributed to 'The Voyage of H. M. •S. Challenger,' on the kinetic theory of gases, on impact and on quaternions.
The third series just published by the Cambridge Press is the 'Papers on Mechanical and Physical Subjects', by Prof. Osborne Reynolds, of Owens College. The first volume contains forty papers from transactions and journals issued from 1869 to 1882. The most elaborate memoir is that on certain dimensional properties of matter in the gaseous state, which includes experiments on thermal transpiration of gases through porous plates and a theoretical extension of the dynamic theory of gas. Many of the papers, such as those on meteorological phenomena and the steering of vessels, are of popular interest. The Cambridge University Press is performing a work of the utmost value to science in undertaking the publication of these great volumes, and we can only regret that, in spite-of the beginnings made at Johns Hopkins, Chicago, Pennsylvania and Columbia, American men of science have no such opportunities for the publication of their works as those afforded at Cambridge and Oxford.
That a large amount of popular interest centers in the study of tree life and all subjects incidental to forestry and horticulture is evidenced by the appearance of a second book on the subject under the title of 'Our Native Trees and How to Identify Them' (Scribners), by Harriet L. Keeler. The volume in question takes up the trees native of northern United States east of the Rocky Mountains, together with a few well-known foreign species which have become naturalized in this region.
The book opens with a key to the families of dicotyledonous species based upon leaf characters, and every species receives not only a full technical description, but also comes in for interesting comments upon habit and general ecological relations. Numerous drawings and half-tones add to the accuracy and clearness of the descriptions. It is not too much to say that the photographic reproductions surpass in beauty and presentation of detail any recent botanical publication, and the venation of leaves is shown in most instances by this method quite as well as it might be done by means of pen and ink sketches. Tne value of the descriptions is heightened by the inclusion of notes of economic interest. It is not unexpected that some errors should creep into the discussions on almost all phases of botany which are interspersed throughout the volume.
The appearance of a new botanical dictionary is most timely, and it is fortunate that the task of its preparation should be undertaken by such a skilful bibliographer as Mr. B. D. Jackson. His 'Glossary of Botanical Terms' (Lippincott) contains fifteen thousand words, or three times as many as have been included in any previous work of this character. This is indicative of a most energetic pursuit of investigations in all departments of the subject, and also of a lamentable tendency to the coinage by botanists of new and unnecessary terms upon the slightest pretext. A legitimate factor in the increase of the contents of such a work consists in the inclusion of words in common use which take on a technical meaning in botany: such, for instance, as altitude, abnormal, abrupt, absolute, accidental back, etc.
Derivations are given, but the history of the terms has not been attempted. According to the author, 'anlage' may be variously rendered as rudiment, inception or primordium. 'Chlorophyll' receives the double consonant at the end of the last syllable against the popular extra-botanical practice. Regarding 'medullary' the author says: "I have given the accent as it is always spoken (medul'-lary) though all of the dictionaries (botanical?) accent it as med'-ullary except Henslow's." In this the author had in mind the practice among his insular colleagues only, since the latter pro-