Page:Popular Science Monthly Volume 48.djvu/635

Rh concerning sun spots, such as Schæberle's and Oppolzer's, and an account of Dunér's and the author's work on sun-spot spectra; a summary of recent progress in prominence photography, etc.; facts and conclusions concerning the corona, based on recent eclipses; an account of Langley's infra-red spectrum investigation, and of the work of De Chatelier, Wilson, Gray, and Scheiner on solar radiation and temperature; and, finally, a most interesting supplementary note, already mentioned, on Helium. The size of the volume has been increased by nearly thirty pages, and the number of illustrations has been raised from eighty-two to one hundred.

The Sun, in its new form, certainly deserves, and will unquestionably obtain, an even greater circulation than that which it has hitherto enjoyed.

"Live" natural history is what Prof. Miall would lead the young naturalist to. While he has no disparagement for systematic zoölogy, he wishes to revive an interest in the writings of Swammerdam, Réaumur, Lyonnet, and De Geer, and to promote that observation of the structure and habits of living animals which those authors pursued with most profitable results. In so doing, he is only restoring a balance that has been disturbed of late years. It is certainly an attractive field into which our author invites the amateur. Who does not love to follow a stream through its alternations of still deeps and rippling shallows, or to stroll along the shore of the ever-moving sea? Whether one be occupied with sport or science, the movement of the water and the succession of traces of its action upon the land yield no small enhancement of pleasure. Aquatic insects do not form a distinct class. Representatives of eleven orders are described in this book, so that the spice of variety is not wanting in their study. Under the guidance of Prof. Miall one may watch at leisure the swiftly darting whirligig beetle or examine the fine case of instruments of the female gnat (there are no mosquitoes, our author says, in zoölogy). Other insects classed as aquatic, because they pass their larval and pupal stages in water, are drone flies (the oxen-born bees of the ancients), dragon flies, pond-skaters, tube-making caddis-worms, etc.; all are air-breathers in the adult form. A phenomenon which profoundly affects the lives of these creatures is the surface film of water. By curious adaptations they take advantage of its tension, while on the other hand some minute creatures find it a death-trap. The reader must not look for a severely logical arrangement in this book. There is an introduction in which the invasion of the waters by insects, the surface film, live natural history, and other topics are discussed philosophically. Directions for capturing specimens will be found not among the preliminary matter, but on page 114, and there are biographical notes about the old naturalists where the first extended citations from their respective writings occur. In the illustrations sufficient magnifying power has been used to make the organs of the insects readily distinguishable, with the result of giving some of the little creatures a truly formidable appearance.