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Page:Popular Science Monthly Volume 35.djvu/596

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THE POPULAR SCIENCE MONTHLY.

a covering for his frizzly hair. On another visit from the natives, one was horrified at seeing salt beef in a cask, and another was terrified at seeing his own ugly reflection in a mirror. They had become tired of the white men by this time, and signified it by waving their arms down-stream. "One very old and wrinkled man rubbed his nose and pinched the tip of it, and rubbed the pit of his stomach. Another signified by signs the act of cutting off the head and arms, using the words 'oorar' and 'badinar.'" With a tribe called Kiwa Pori, in the delta of the Queen's Jubilee River, one of the signs was to hide their lowered heads in their hands and then to draw their hands down ever cheeks, mouth, chin, neck, breast, and abdomen. These men were of unusually fine stature, and dark bronze in color; but, though with well nourished and muscular frames, "their retreating foreheads and heavy eyebrows gave them a sinister expression." One tribe always spoke the name of the sun in a whisper, with finger pointing upward and averted gaze. In a deserted hut, which exceeded the others of the village in size, was found fixed up in front a "taboo," consisting of a painted mask resting on a large circular wisp of sago-palm fiber and rattan, with pendent streamers of the same fibrous material; while half-way down the floor of the hut were bones of fishes and small deer suspended from streamers. All of the new tribes wore nose-pencils, distended the lobes of their ears, and smoked sun-dried tobacco by means of bamboo tubes. The canoes of all the tribes were dug-outs, with either a bank of mud or a small boy squatting in the prow and opposing his back to the incoming water. Some of them were very large. In one, twenty-nine men stood up to paddle.

 

Polishing Telescopic Objectives.—The shaping and grinding of telescopic objective lenses are operations requiring great care and delicacy in execution. In polishing, softer powders and softer tool-surfaces must be used than in grinding. Of all the substances that have been used for the face of the polisher, pitch, or the natural bituminous deposit from Archangel, which was first employed by Sir Isaac Newton, is, according to Mr. Howard Grubb, still the best. It has the important qualities of perfect inelasticity and a property of subsidence. Cloth can not give a perfect surface, because it is apt to round off the edges of the pits left by the grinding-powder, and to polish their bottoms as well as the real surface of the lens. Pitch wears away the surface evenly, and does not take hold of the pit-bottoms till the whole is ground down to a level with them. Although pitch, by boiling, can be made so hard that an impression can not be made on it with the finger-nail without splitting it in pieces, it will, even in this condition, if laid on an uneven surface, in time subside and take the form of whatever it is resting upon. This property, by virtue of which it may be considered technically a liquid, is taken advantage of in the manipulation of the polishing process to produce a surface exactly even and true. It appears to be peculiar to pitch, some of the resins, and ice; although it has been observed, in a vastly inferior degree, in some metals. It is a curious circumstance that the same quality which in ice allows gradual creeping and subsidence, and the consequent formation of glaciers, should in pitch help us to produce accurate optical surfaces.

 

Italian Butter.—The Italians do not excel in the manufacture of butter. It is produced considerably only in four districts, of which Lombardy furnishes the best, usually through the market of Milan. The butters of Reggio and the Tyrol are used for mixtures, and those of Æmilia and Sorrento are unimportant in quantity. In the rest of the country, oil, fat of American origin, or substitutes are used for daily wants. According to the French consul at Milan, the principal obstacle to the development of the trade in pure butter is the increasing use of these substitutes, and artificial butters, which are imported from America, France, Germany, England, and the Netherlands. "The demand for butters in Europe, South America, Australia, India, Japan, and even China, has become so important that, in presence of the insufficiency of the natural product, it became necessary to manufacture an analogous substance, so that in Holland and Denmark, the principal countries producing pure butter, the artificial butter industry was undertaken without fear of prejudicing the pure