Page:Popular Science Monthly Volume 40.djvu/139

Rh working student it is far too meager, and lacks references to original material; as a popular book for the uninformed it is too condensed to be of much use. At the outset a list of books is given for consultation, and this will strike one as a curious collection for the purpose. In the preface the author says, "I am at a loss to imagine why it is considered almost wrong to write about physical science without having made original experiments." The advantage of having made original experiments leads a writer to greater exactness, and, above all, to appreciate the relative value of statements and facts. Her allusions to the fixed ascidians as being comparatively free from vicissitudes and dangers in contrast with locomotive forms derived from the same stock, is misleading. The helpless creature nibbled at by fishes, infested by extraneous growths, unable to fight or flee, is seriously handicapped in the struggle for existence.

We know of no evidence to show that the duration of life of a species is governed other than by the law of natural selection. An interesting article, by Prof. Verrell (Science, vol. i, p. 303), would have given the author some hints as to the probable cause of the rapid disappearance of the larger vertebrates in past times. An allusion is made to the divergence of the Ainos from the Japanese, whereas the Ainos covered the islands of Japan before the Japanese were crystallized into a nation.

Silly flights of fancy are quite out of place in a serious work of this nature; but the attempt to enliven a dignified discourse by lugging in extracts of poetry or nonsense is peculiarly English, and so must be endured.

The Progress Report on Irrigation in the United States, prepared by Special Agent Richard J. Hinton, on account of the shortness of time during which the survey had been at work when it was made (sixty-one days), does not include results of the investigation itself, but only the returns of correspondence with experts and persons interested in the subject, invited in order to show the conditions and development of irrigation as applied to the soil for the purposes of cultivation. The large number of letters received shows how extensive and growing is the interest in the subject, and promises that the office of the irrigation inquiry will soon have a record of all that has been done about it. As among our own people, practical irrigation appears to have begun with the Mormon settlement on the Great Salt Lake; but has been practiced by the Indians in Arizona and New Mexico for five hundred years. General irrigation really began in the United States with the foundation of the colony at Greeley in Colorado, in 1870, which was successful at once. Its development, slow till 1880, has been more rapid since then. One of the sequences of its adoption is the appearance of a tendency toward division of large holdings of land and its more or less rapid disposal in small bodies. Another incident is a movement among land, mortgage, and trust companies to form syndicates for developing the water-supply of the plains country, for the purpose, of course, of improving the security for their loans. Horticulture in California is said to be in great part the result of irrigation, as is illustrated in the great fruit farms at Riverside. Much stress is laid upon the value of the "undersheet water" of the Arkansas and Platte and other valleys, the results of the survey of which, by Chief-Engineer Nettleton, are noticed below. The curious fact is mentioned concerning this water that cultivation tends to draw it up. Thus at Fresno, where the first cultivators had to dig fifty feet for it, they now get it at from eight to twelve feet below the surface.

The Report of Artesian and Underflow Investigation between the ninety-seventh degree of west longitude and the foot-hills of the Rocky Mountains, presented by Edwin S. Nettleton, in response to a call by the Senate, is also a progress report, and relates to work done in November and December, 1890, in parts of Kansas, Nebraska, and Colorado, covering particularly the valleys of the Platte and the Arkansas. Valuable features of the report are the plan and profiles showing in detail the location and relation of the surface of the underground water, as found in rivers, wells, springs, and pools, as well as the elevation of the surface of the country along the line surveyed. There appears to be usually sufficient rainfall in this region during the whole year, if it were