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A primitive chart prepared by the Polynesians to assist them in their travels from island to island has been acquired by the British Museum. The chart in question refers to the Marshall Islands, and was prepared by the natives. Routes, currents, and prevailing winds are represented by pieces of split cane, straight or bent according to the chart-makers' knowledge of the facts of the case, while the islands are indicated by univalve shells attached to the canes. The heat of fusion has been studied by A. W. Smith. (Phys. Rev.) In the determination of the constant the ice in small pieces was previously cooled several degrees below 0 deg. C., and after weighing was transferred to the calorimeter containing kerosene oil already cooled to the same temperature. Heat was supplied by means of an electric current, the amount of heat being calculated by measuring both the current through the coil in the calorimeter, and the E. M. F. between its terminals, in terms of a standard cell. The preliminary value given for the constant is 334.25 joules as the mean of eight determinations of the heat of fusion of ice, in each of which about 100 grammes of ice was melted. On passing a current of hydrogen through a silica tube heated until soft in an oxyhydrogen flame, a deposit of silica, either alone or mixed with silicon, is formed in the tube, the silica being reduced by the hydrogen forming silicon hydride and water vapor, which react together in the reverse direction at a slightly lower temperature. When, however, this reverse reaction is incomplete, some of the silicon hydride is decomposed, yielding silicon and hydrogen. A silica rod loses weight when heated in an oxyhydro-gen flame, a rod 970 milligrammes in weight losing 500 milligrammes in 15 minutes. That the above-described deposition of silica and silicon is not due to the volatility of the silica and its partial dissociation is proved by Moissan's work, which showed that silica is not appreciably volatile at the temperature of these experiments. Further, if oxygen or carbon monoxide is passed through the silica tube in place of hydrogen, no deposit forms. The loss in weight of the silica rod when heated varies with the nature of the gas employed as source of heat, being greatest for a mixture of oxygen and hydrogen, and least for oxygen with carbonic oxide. On immersing in cold distilled water a rod of one of the four non-crystalline tin-aluminium alloys, Sn5Al. SnsAl, Sn,Al, and SnAla, the surface of which has been worked with the file, an abundant evolution of detonating gas takes place for two or three minutes at the field surface of the alloy. This phenomenon is not observed with (1) a previously heated or filed tin or aluminium rod, or (2) a rod of the alloy not filed but heated to the same temperature as is produced by the filing. These tin-aluminium alloys must be formed, except at the hardened surface, by the juxtaposition of the molecules of the two metals, so that the filed surface acts with the distilled water like a number of small thermo-electric couples which immediately decompose the water. Boiling distilled water is decomposed by the non-filed tin-aluminium alloy, the heating apparently destroying the combination of . the metals at the surface. If a filed tin-aluminium rod is dipped into a faintly acid copper sulphate solution, oxygen is evolved and copper deposited; a non-filed tin or aluminium rod, however, precipitates the copper but gives no gas evolution. Zinc sulphate behaves like copper sulphate, but the development of oxygen is not so vigorous. Lead-aluminium alloys are described by H. Pecheux in Comptes Rendus. Molten mixtures of aluminium and lead, containing less than 90 per cent of the former metal, separate, on cooling, into three layers, the lower one consisting of lead, the middle one of an alloy' containing 90 to 97 per cent of aluminium, while the tipper one is aluminium. Of the alloys obtained in this 'way, those containing respectively 93, 95, and 98 per cent of aluminium have the densities 2.745, 2.674, and 2.600, and have nearly the same color as aluminium; they are malleable and are readily cut with the .chisel, showing a silvery surface, but are not so hard as aluminium and are easily bent. That they are not definite compounds is shown by the fact that, when re-melted and cast, they yield alloys containing 92, 94, and 96 per cent respectively of aluminium and having the densities 2.765, 2.691, and 2.671. This tendency to liquate necessitates the rapid cooling of the molten alloys. The alloys do not oxidize in moist air or in the molten state. They are attacked at ordinary temperatures by concentrated hydrochloric or sulphuric acid with evolution of hydrogen, and by hot sulphuric acid which evolves sulphur dioxide and by hot nitric acid with generation of nitric oxide; the latter acid has little action in the cold, and the same is the case with dilute acids, even -when heated. Concentrated potassium hydroxide 'solution and aqua regia act vigorously even in the cold, but distilled water is without action even at the boiling point; hydrogen sulphide blackens to a slight extent the alloys containing 92 and 93 per cent of aluminium. Scientific American October 22, 1904.
