Potash – aeas精读训练 (10-12年级)
Potash (the old name for potassium carbonate) is one of the two alkalis (the other being soda, sodium carbonate) that were used from remote antiquity in the making of glass, and from the early Middle Ages in the making of soap: the former being the product of heating a mixture of alkali and sand, the latter a product of alkali and vegetable oil. Their importance in the communities of colonial North America need hardly be stressed.
Potash and soda are not interchangeable for all purposes, but for glass- or soap-making either would do. Soda was obtained largely from the ashes of certain Mediterranean sea plants, potash from those of inland vegetation. Hence potash was more familiar to the early European settlers of the North American continent.
The settlement at Jamestown in Virginia was in many ways a microcosm of the economy of colonial North America, and potash was one of its first concerns. It was required for the glassworks, the first factory in the British colonies, and was produced in sufficient quantity to permit the inclusion of potash in the first cargo shipped out of Jamestown. The second ship to arrive in the settlement from England included among its passengers experts in potash making.
The method of making potash was simple enough. Logs was piled up and burned in the open, and the ashes collected. The ashes were placed in a barrel with holes in the bottom, and water was poured over them. The solution draining from the barrel was boiled down in iron kettles. The resulting mass was further heated to fuse the mass into what was called potash.
In North America, potash making quickly became an adjunct to the clearing of land for agriculture, for it was estimated that as much as half the cost of clearing land could be recovered by the sale of potash. Some potash was exported from Maine and New Hampshire in the seventeenth century, but the market turned out to be mainly domestic, consisting mostly of shipments from the northern to the southern colonies. For despite the beginning of the trade at Jamestown and such encouragements as a series of acts “to encourage the making of potash,” beginning in 1707 in South Carolina, the softwoods in the South proved to be poor sources of the substance.
钾肥（碳酸钾的旧名称）是两种碱中的一种（另一种是苏打，碳酸钠），它们在远古时代用于制造玻璃，从中世纪早期用于制造肥皂：前者是加热碱和砂混合物的产物，后者是碱和植物油的产物。它们在殖民地北美社区中的重要性几乎不需要强调。 钾盐和苏打水不能用于所有目的，但对于玻璃或肥皂制造，任何一种用途都可以。苏打水主要来自某些地中海植物的灰烬，来自内陆植被的钾肥。因此，对于北美大陆的早期欧洲定居者来说，钾肥更为熟悉。 弗吉尼亚州詹姆斯敦的定居点在许多方面是殖民地北美经济的一个缩影，钾肥是其首要关注的问题之一。它是玻璃厂的必需品，是英国殖民地的第一家工厂，并且生产量足以允许在从詹姆斯敦运出的第一批货物中加入钾肥。第二艘抵达英格兰定居点的船只包括其乘客的钾肥制造专家。 制作钾肥的方法很简单。原木堆积在一起并在露天焚烧，灰烬收集起来。将灰烬放入桶底部的孔中，并将水倒在它们上面。从桶中排出的溶液在铁水壶中煮沸。进一步加热所得物质以将物质熔化成所谓的钾碱。 在北美，钾肥生产很快成为农业用地清理的附属物，因为据估计，通过出售钾肥可以收回清理土地成本的一半。一些钾肥在十七世纪从缅因州和新罕布什尔州出口，但市场主要是国内的，主要是从北部到南部殖民地的货物。尽管在詹姆斯敦开始贸易，并且在1707年开始在南卡罗来纳州开展了一系列“鼓励制作钾肥”的行为，但南方的软木被证明是该物质的不良来源。