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Page:Popular Science Monthly Volume 56.djvu/753

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FRAGMENTS OF SCIENCE.

found the Ophir whence King Solomon's gold was brought, in the country between the Zambesi and the Pungwa Rivers, in Portuguese Africa and eastern Mashonaland. Many rivers, some quite extensive, of undetermined origin, and traces of ancient mining enterprises, are found in the region, and gold is still washed there. One site is Fura, on the Muira River, about fifteen miles south of the Zambesi. The name Fura is said to be a native corruption of the word Afur, by which the Arabs of the sixteenth century called the district, and that to be the Saharan or south Arabian form of the Hebrew Ophir. The natives are unlike the ordinary Africans, and have a distinctly Jewish type of face. A chief informed Dr. Peters concerning the position of some ancient workings, and, following his directions, the explorer found ruins "of an undoubtedly Semitic type." Dr. Peters's hypotheses and evidences must be accepted for what they are worth. Other explorers have found Ophir at various points in Africa and Arabia, and even in India and elsewhere, and have been as satisfied and as sure as he with their identifications.


MINOR PARAGRAPHS.

An instructive address, before the Iron and Steel Institute of Great Britain, was recently delivered by Sir W. Roberts Austen on the progress made in the iron and steel industries during the past century. The great revolution which the discovery of steel brought about is dwelt upon at length, and its far-reaching importance, not only in the iron industry itself but in all other industries and in the destinies of England herself, pointed out. In the early days of the industry it was held that the different qualities of iron were due to the different localities from which the ore was obtained, but late in the eighteenth century the great Swedish chemist, Bergman, of Upsala, clearly showed that carbon is the element to which steel and cast iron owe their distinctive properties. Clouet's celebrated experiment on the carburization of iron by the diamond followed. "Well might Bergman express astonishment at the action of carbon on iron. Startling as the statement may seem, the destinies of England throughout the century, and especially during the latter half of it, have been mainly influenced by the use of steel. Hardly a step of our progress or an incident of our civilization has not in one way or another been influenced by the properties of iron and steel. It is remarkable that these properties have been determined by the relations subsisting between a mass of iron, itself protean in its nature, and the few tenths per cent of carbon it contains." In 1800 the production of pig iron in England was about 200,000 tons; in 1898 it was 8,769,249 tons.

A note in Nature describes an ingenious arrangement for controlling the direction of torpedoes by means of ether waves. Two solenoids, into which are drawn iron cores, are attached to the rudder head, the core which is drawn in depending, of course, upon the direction of the received current. Two rods projecting above the surface of the water receive the waves and are in circuit with a coherer of special type, which affects a relay in the usual way. The actual processes involved in steering and controlling a torpedo are somewhat as follows: The torpedo, containing a suitable combination of the apparatus above mentioned, is launched from a vessel containing the necessary sending apparatus. Suppose the torpedo goes off its course. Then, by means of a switch, an induction coil is supplied with an electric current, and waves or oscillations are generated. These, on reaching the torpedo, pass into the projecting wire and thence reach the coherer. This operates the relay, closing the secondary circuit. An electric current now flows through a "selector" to one of the solenoids, the iron core is sucked into right or left, and the helm is thus turned. When the torpedo has attained a proper course the switch is opened and the waves cease. The vibration in the neighborhood of the coherer restores it to the original resistance; the current passing through it becomes weaker and ceases to affect the relay coil, which therefore opens the secondary circuit and allows the helm to fly back to the midship position. A large model of the apparatus has been constructed, and it is said to work with en-