Page:Popular Science Monthly Volume 8.djvu/515

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the first of these two little volumes the practical builder will find a discussion of the most important and common cases of horizontal beams under vertical loads. The problems are worked out without having recourse to the higher mathematics. The second volume contains, in abridged form, a series of lectures delivered by Prof. Corfield before the School of Military Engineering at Chatham, England. The question of sewerage and sewage utilization is one of the urgent problems of modern life, and it yet awaits satisfactory solution. Meanwhile, Mr. Van Nostrand does the public a service by placing within the reach of all the views of so eminent an engineer as Prof. Corfield upon these subjects.

here, in the first place, briefly considers the question of the origin of the ceramic art. When, where, how did it originate? No positive answer can be given to these questions. Like other human arts, it is the result of a long evolution, and its simple beginnings we may never be able to find out. So much, however, is certain, namely, that the finest porcelain wares are the true lineal descendants from the pottery of the savage. The author next considers the materials employed and the methods followed in the building of a vessel. Before the advent of Europeans, pottery in America was made by hand, the potter's wheel being unknown. He finds the method of fashioning vessels out of coils of clay widely practised in South America. The manufacture is everywhere exclusively in the hands of the women.

is a reprint of a communication in Nature by Mr. John Ericsson, in which he points out defects in Father Secchi's method of measuring the intensity of the sun's radiant heat. Secchi's method is that of projecting the sun's image on a screen, and then measuring the temperature at different points by means of thermopiles. Ericsson adopts the method of direct observation, and employs a special apparatus devised by himself. Mr. Ericsson estimates the absorption by the solar atmosphere at not over 0.144 of the radiant heat emanating from the photosphere. The intensity of radiation from the border of the sun he estimates at 0.638 of the intensity of radiation from an equal area of the central region.

the twelve hundred North American species of Noctuæ, less than thirty, we are informed by Mr. Grote, are considered identical with European forms. The facts seem to point to a common origin of many of the forms, and it is the author's opinion that the European and North American Noctuæ are in part descended from species living over a common territory, and that the Glacial epoch separated the stocks. The list of species here given includes a complete synonymy of the Noctuidæ of America north of Mexico, so far as known. It is invaluable to the student of entomology.

considers the subject of insanity in the six New England States. He finds that in Massachusetts, from 1850 to 1870, the increase of insanity was 12 per cent, greater than the increase of population, and the same is to be said of the other New England States. He favors consigning the chronic insane to homes, instead of keeping them in hospitals. What they need is, not medical treatment, but suitable exercise, sunlight, air, proper nourishment, etc. He also advocates the adoption by the State of measures for the prevention of insanity. The dissemination of more correct views of the true way of living and a more rigid observance of the laws of health and Nature would, no doubt, greatly diminish the frequency of mental disease.