# Popular Science Monthly/Volume 56/April 1900/Minor Paragraphs

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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 ​entire success under all kinds of conditions. The inventors are Mr. Walter Jameson and Mr. John Trotter. It is stated that Nikola Tesla has American patents for a somewhat similar device.
In the absence of the author, Professor Dewar's paper on the solidification of hydrogen was read in the British Association by Sir William Crook. It shows that solid hydrogen presents the appearance of frozen water, and not, as had been anticipated by many, of frozen mercury; hence it is now definitely decided that it is not metallic. The temperature of the solid is 16° absolute at thirty-five millimetres pressure, and it melts at 16° or 17° absolute, the practical limit of the temperature obtainable by its evaporation being 14° or 15° absolute. This the last of the old gas has been solidified. It was further mentioned, in connection with these statements, that Professor Dewar had succeeded in liquefying helium.
The organizing committees of the Congresses of Aëronautics and Meteorology—these being cognate subjects—of the Exposition of 1900 have decided to hold the meetings of these bodies in such a manner that all members can attend the sessions of both. The programme arranged for the Aëronautical Congress contemplates the discussion, under aspects which are set forth in detail, of "problems" relating to free balloons, their management and use; captive balloons, steerable balloons, and aviation; and the scientific applications of balloon observations to problems in astronomy, meteorology, and physiology; also of their use for purposes of reconnoissance and topographical surveys, and of photography from balloons. In a different order of ideas, the congress may occupy itself with questions of legislation and international law which concern aëronauts in times of peace and of war.
Three State catalogues of Ohio plants have heretofore been issued. The first, by J. S. Newberry, was published in the State Agricultural Report in 1859; the second, by H. C. Beardslee, was published in 1874, and was reprinted in the Agricultural Report for 1870; and the third, by W. A. Kellerman and W. C. Werner, was included in the State Geological Report for 1893. This work contains a bibliography, and gives the names of the first known collectors of the less common species. A fourth catalogue, consisting of a checklist of the Pteridophytes and Spermophytes, recently published by Prof. W. A. Kellerman, contains the species and varieties numbered serially, as in the State Herbarium of nearly ten thousand sheets, with the sequence of groups as by Engler and Prantl, and the nomenclature as used by Britton and Brown.