Page:Popular Science Monthly Volume 47.djvu/137

Rh devoted, with numerous subheadings, to the discussion of temperature and pressure and their variations, evaporation, clouds, rain, and snow; winds, thunderstorms, and tornadoes, and optical appearances. A full chapter is given to the exposition of the construction and meaning of weather maps, and another chapter to the consideration of the import of weather predictions. A short account of river floods is given, and the method of predicting river heights for a number of points along the lower Mississippi River and its tributaries. In all this a general view is taken of meteorology, while climatology is treated of only in its broad, general features. The principal weather changes are described as they occur in various parts of the world in different seasons on land and sea, and their causes are narrated as far as is known. A collection of facts is given useful in forming a conception of the phenomena of the atmosphere as a whole, so as to enable those with little time for consulting a multitude of books to form a notion of the science of meteorology as it is at present.

object of this volume—which has been prepared by a special committee appointed to collate the field notes of members of the club—is to provide these members and ornithologists with a summary of our present knowledge of the birds of the district included, with regard to their abundance, distribution, and time of occurrence. Description of the birds and their habits does not come within the scope of the work. In the preliminary pages are given notes on the geographical distribution of birds; the faunal areas of the region; their physical features and characteristic birds; the distribution of winter birds; a general discussion of bird migration; migration in the vicinity of Philadelphia; and birds found within ten miles of Philadelphia—conveying copious information. The region is crossed by the three faunal zones: the Carolinian, occupying the southeastern corner of Pennsylvania and the whole of southern New Jersey, to the Hudson and beyond, with a bay up the Susquehanna Valley; the Alleghanian, occuing the rest of the region, except the tops of the higher mountain ranges and portions of the elevated table land in the north central part of Pennsylvania, where the Canadian zone is represented. The passage from the Alleghanian to the Canadian zone is, as a rule, remarkably distinct, as the more northern birds keep strictly to the virgin forest. Where the forest has been removed, the Canadian species for the most part disappear. These three faunal zones are divided into several well-defined regions which differ more or less in their physical features, and consequently in the character of their bird life; and these are described.

proposal to hold the conference of which the proceedings are recorded in this book originated with Prof. A. F. Zahm, of Notre Dame University, who communicated with Mr. C. C. Bonney, President of the World's Congress Auxiliary, and interested several other persons in the project. The principal objects of the conference were to bring about the discussion of some of the scientific principles involved in the scheme of aerial navigation; to collate the results of the latest researches; to procure an interchange of ideas; and to promote concert of action among the students of this inchoate subject. The programme involved, first, a discussion of the general principles of the subject, and more special discussions in Sections A and B, under the heads of Aviation and Ballooning. Letters of co-operation were received from experts or students of the subject, and from the British Aëronautical Society, the Aerial Navigation Society of France, the Aviation Society of Munich, the Imperial Aëronautical Society of Russia, and the Aviation Society of Vienna. The sessions were attended by about one hundred persons, who seemed to take great interest in the proceedings, and the discussions brought out several investigators who had been studying the subject or trying