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现在已知的100种元素(参看本刊七卷九期第5面1952年苏联原子量表)中,有(2/3)强为金属,而这些金属之为普通常见的却不满十余种。金属的用途主要决定于蕴藏丰富,易于提炼及其性质。现代科学日益进展,因之更需巨量金属产物以供各种用途,除非自然界能大量供应,否则不论该金属所具性质如何优良;其用途终必被限制。例如铂的供应量如能以吨计,而不以唡计,则很可用之为建筑材料。金属每因提炼的困难,以致影响其价格及大量生产。有时由于某种金属从来未能炼得纯品,致掩没其真实性质,如蕴藏丰富,但极有用的钛。锌、锡、汞等的性质虽稍差,却因易于冶炼,故数千年来一直为人们所使用。金属的性质当然是最应注意的,铀及镭所具的宝贵性质,超越其稀少量及提炼的困难,而蕴藏丰富且易提炼的钠及矽,则与其使用范围还不能相称。表1系根据地壳下十哩内金属蕴藏量的多少次序排列,以铝为100作为比较。某些稀金属每集中一处,故易于发见,因此表1并非表明金属的位置与其立可利用的直接关系,但供参考而已。
Of the 100 elements now known (2/3 of the 100 elements of the Soviet atomic weight scale, Table 5, Vol. 7, No. 9, the Soviet atomic weight scale), two or three of these elements are strong metals, which are less common than ordinary ones but less than ten. The purpose of the metal is largely determined by its abundance, ease of refinement and its properties. As modern science advances, it requires more and more huge amounts of metal products for a variety of purposes. Unless nature can supply large quantities, no matter what the nature of the metal is, the use of the metal must eventually be limited. For example, if the supply of platinum in tons, rather than lenght, it is very useful as building materials. Each metal is so difficult to extract that it affects its price and mass production. Sometimes the true nature of a metal, such as rich but extremely useful titanium, is sometimes obscured by a metal that has never been purified. Although zinc, tin, mercury and other properties of a slightly worse, but because of easy smelting, it has been used for thousands of years. The nature of the metal is, of course, the most notable one. The precious properties of uranium and radium, beyond their sparse amounts and difficulties of extraction, are not comparable to those of sodium and silicon that are abundant and easily refined. Table 1 is based on the number of metal deposits within 10 miles below the Earth’s crust, according to the order of aluminum to 100 for comparison. Since each of the rare metals is concentrated in one spot, it is easy to see the results. Therefore, Table 1 does not indicate the direct relationship between the position of the metal and its availability, but for reference only.