Page:Popular Science Monthly Volume 47.djvu/582

568 becomes definite, for all the loads are sure to be concentrated at the column centers that carry them. Kindred to this change is the large independence of partition walls which the steel construction makes possible. Another radical change, and the most conspicuous to the eye that steel has introduced, is in the height of large buildings. Steel buildings—their construction admitting of unlimited bracing—may be carried to any height, the only restrictions being those imposed by the character of the foundations, the land, and economical considerations. The steel construction admits a vast increase of window space, the masonry walls which had to be built for strength being no longer required, and their place may be taken by glass.

The Weather and Mental Action.—Who has not felt the difference between a depressing and an exhilarating day? Sydney Smith wrote: "Very high and very low temperatures establish all human sympathy and relations. It is impossible to feel affection above seventy-eight degrees or below twenty degrees." Dr. Fair and Dr. Stark almost lead us to think morality is registered on the thermometer, so surely does it measure certain kinds of criminality. On suicides the effects of the weather are well known. Nearly all vocations are affected by weather. Men of science are often as much subject to weather as seamen. Some writers must have the weather fit the mood, character, or scene. If one will read poetry attentively, he will be surprised to find how many weather marks are scattered through it. Diverse weather states may be one cause of so much diversity and even disagreement in thought processes usually regarded as scientific. Many experienced teachers think there should be modifications of school work and discipline to correspond with the weather. The head of a factory employing three thousand workmen has said, "We reckon that a disagreeable day yields about ten per cent less work than a delightful day, and we thus have to count this as a factor in our profit and loss account." These are some of the ideas put forth in a preliminary statement by J. S. Lemon, who proposes to publish more at length upon the subject. "Laboratory investigation of the subject," he says, "meets at the outset the difficulty of distinguishing results of weather changes from similar states otherwise caused. This difficulty is no greater than in many other topics of research, and we believe will not invalidate our methods and results."

Characteristics of Recent Geological Study.—If one were asked, says Sir Archibald Geikie, to specify the feature which above all others has marked the progress of geology in Britain during the past five and twenty years, he would reply, the enlarged attention given to the study of the rocks, or petrography; and this study has been revolutionized by the introduction of the microscope as an adjunct to research. The rocks of the country have become a foremost object of study. In stratigraphical geology a much closer attention than ever before has been given to the investigation of the most ancient accessible parts of the earth's crust. The fundamental platform on which the fossiliferous rocks repose has been searched for and has been detected in several places where it was not before supposed to exist. We know more clearly than before the general outlines of two or more great geological periods anterior to the earliest relics of animal life. Among the applications of paleontology to the stratigraphical side of geology the most important in recent times has been the recognition of life zones among the stratified formations and the adoption of these as a clew to the interpretation of the sequence of strata, and even under some risk of error of tectonic structure. In the department of geotectonics one of the most interesting features has been the increased attention bestowed upon the nature and results of the great movements that have affected the crust of the earth. Another distinguishing characteristic of the period has been the increased interest taken in the history of the earth's surface or its superficial topography as contrasted with the almost exclusive attention given by the older geologists to the story of the rocks. The views respecting the possible age of the earth have undergone several modifications by geologists and physicists alternately, with accepted periods ranging from four hundred millions down to ten millions of years. The latest phase of them is that put forward by