Page:Popular Science Monthly Volume 33.djvu/440

426 oils by the process of absorption, and of essences and essential oils by distillation. To make pomade, a square frame or chassis of white wood, about twenty by thirty inches, is set with a pane of strong plate glass. On either side of the glass is spread a thin, even layer of purified and refined grease. These frames are prepared beforehand, and kept for the time of the flowers. This having arrived, the petals are picked from the blossoms and laid so as to cover the grease in each frame. These are piled one upon another so as to fit closely together, when there is formed a kind of tight chamber, the floors and ceilings of which are of grease exposed to the perfume of the flower-petals within. The grease absorbs the perfume, while the spent flowers are removed daily and fresh ones supplied for two, four, or five months, according to the strength of perfume desired in the pomade. The perfume may afterward be extracted from the pomade by alcohol, when it becomes a floral water or extract. Coarser pomades are made by boiling the flowers in the grease, and subjecting the residue to pressure. The spent pomades are used for toilet purposes, and in the manufacture of fine soaps. When perfumed oils are wanted, superfine olive oil is used, and cotton cloths saturated with it take the place in the chassis piles of the grease coating on the glass. Essences and scents are produced by ordinary distillation.

The Best Asphalt.—No artificial mixture of bitumen and calcareous matter, says Mr. W. Y. Dent, in a lecture before the Society of Arts, is so well adapted for the description of asphalt used for road-making purposes as the natural deposits found at Val de Travers and at Seyssel. Its superiority is possibly due to the perfect manner in which, by the enormous pressure to which the deposits have been subjected, the ingredients of the rock have been incorporated. The native asphalt rock consists for the most part of carbonate of lime, more or less impregnated with bitumen, the quantity of which varies from about six to twelve per cent, that from the Val de Travers, in the canton of Neufchâtel, containing rather more bitumen than that of the Seyssel. The prepared asphalt, as sold by the makers under the name of "mastic," is made by crushing the asphalt rock under a steam-hammer and grinding it to powder by edge-runners. The powdered rock is then carried forward by means of an endless screw to cast-iron vessels placed over a fire, in which it is mixed with suitable proportions of fine sand and bitumen and kept constantly stirred for two or three hours, when it is run into blocks weighing about one hundred and twenty pounds. When the mastic is used it is reheated with more bitumen, and coarse sand is added to it in quantities, according to the purpose to which it is to be applied. Co altar pitch is not an entirely satisfactory substitute for bitumen in this mastic, because when hard it is too brittle, and when warm is too soft and sticky.

Geography and its Related Sciences.—Mr. H. J. Mackinder would define geography as the science whose main function is to trace the interaction of man in society, and so much of his environment as varies locally. According to Mr. Bryce, the environment comprises the influences due to the configuration of the earth's surface; those belonging to meteorology and climate; and the products which a country offers to human industry. The first of these categories depends more largely than has been acknowledged on geology, and is related to physiography, which asks, "Why is it?" to topography, which asks, "Where is it?" to physical geography, "Why is it there?" and to political geography, "How does it act on man in society, and how does he react on it?" and itself asks, "What riddle of the past does it help to solve?" We may stop short at any of these questions, but can hardly answer a later one with advantage unless those which preceded it have been answered. Of meteorology, average or recurrent climatic conditions alone—not weather forecasting—come within the geographer's ken. In considering the productions of a region, the distribution of minerals is incidental to the rock structure. The distribution of animals and plants is pertinent in so far as those organisms form an appreciable factor in man's environment, and in so far as it gives evidence of geographical changes, such as the separation of islands from continents and the retirement of the snow-line. But the study of the distribution of animals