Page:The New International Encyclopædia 1st ed. v. 20.djvu/916

ZIMMERMANN. 778 ZINC. best-known work is the Geschichte des grossen liauernkriegs (new ed. 1891), besides which may be mentioned Geschichte Wurttcmbergs (1835-37) , .Die Befreiungskiimpfe der Deutschen gegen Xapoleon (3d ed. 1859), Geschichte der Uohenstaufen (2d ed. 1805), Lebensgeschichte der Kirche Jesu Christi (2d ed. 1869), Deiilsch- lands Ucldenkampf 1S~0-71 (1872), and lilus- trierte Geschichte des deutschen folks (1873- 77). ZIM'MERN, Helkn (1846—). An English author and translator. She was born in Ham- burg, Germany, but was brought to England at the age of four. She received a careful educa- tion at home and at a private school in London. In 1868 she began to write for various journals and reviews, and won almost immediate success. Many of her sketches were afterwards collected in book form, but it was rather as a translator and interpreter of Continental authors than as a story-teller that she became widely known. Among her publications are: Stories in Precious Stones (1873); Schoj)enhauer : His Life and Writings (1878); Half Hours with Fammis Novelists (1880) ; Tales from the Eddas (1882) ; The Epic of Kings, from Firdusi (1882) ; Life of Marie Edgeicorth (1883) ; Hansa Totcns (1889) ; a translation of the Comedies of Goldoni ( 1892) ; the Pentamerone, translated (1893); and Sir Laurence Alma Tadema (1902), aside from trans- lations from Nietzsche and Lessing. ZIM'RI. A character intended to represent Villiers, Duke of Buckingham, in Dryden's Absa- lom and Achitophel. The caricature received high praise from Walpole. Buckingham an- swered it in his Poetic Reflections on a Late Poem entitled, "Absalom and Achitophel." ZINC (Fr. zinc, from Ger. Zink, zinc; con- nected with OHG. sin, Ger. Zinn, AS., Eng. tin, and with Goth, tains, AS. tan, OHG. zein, twig, thin leaf of metal). A well-known metallic ele- ment. In the isolated state it was unknown to the ancients, but coins of brass, of which zinc is a constituent, have been found dating as far back as a.d. 110. Basil Valentine mentions zinc in several of his writings, but it was not until 1520 th.it Paracelsus first described zinc as a metal and assigned it to the class of semi-metals. Its eliaracter as a distinct substance was not fully recognized until the close of the seventeenth century, and even Lemery, in 1075, refers to zinc as being identical with bismuth. The metal has been reported native in small quantities near Melbourne, Australia, and in the United States in northeastern Alabama, but these discoveries need confirmation. Tlie principal ores are the carbonate, or smithsonite; the oxide, or zincite ; the oxide in combination with manganese oxide, or franklinite; the silicate, or calamine; and the sulphide, or sphalerite, usually called blende. Less commonly zinc occurs as the aluminate, the arsenate, the phosphate, and the sulphate. Zinc (symbol, Zn; atomic weight, 65.-U ) is a bluish-white metal with a specific gravity of 0.9. It melts at 419° C. (786" F.) and boils at 1040° C. (1904 F.). It is brittle at ordinary temperatures, but beoomes malle.able between 100° and 150° C. (212° to 300° F.). Commer- cial zinc has a coarse laminar texture; it is mod- erately hard, diniciilt to file, and when bent after fusion emits a crackling noise similar to that of tin. The metal is commonly known in the trade as spelter. It comes into commerce cliielly in the form of sheets and is extensively used in the arts, es- jiecially in the manufacture of brass, German silver, and other alloys (see AliOY) ; also for freeing lead from silver, for galvanizing iron, for electrical batteries, as a chemical reagent, etc. Zinc combines with oxygen to form a monoxide, which may be prepared artificially by burning the metal in air, the product being a slightly yellow pulverulent solid that is known in commerce as zinc-white, and is used as a pig- ment and in medicine. It was the nix alba, 'philosojjhical wool,' or 'flower of zinc' of the alchemists, and the tutia or pompholyx of the ancients. Among other commercial zinc compounds is the chloride (oleum lapidis cala- minaris) , first described by Glauber in 1048. It is prepared commercially by treating scrap zinc with hydrochloric acid and evaporating the re- sulting solution to crystallization. This salt is used in medicine as a caustic, and is a disin- fectant and deodorizer. It finds extensive ap- plication as a preservative of timber, the chloride in the form of a solution being forced by pressure into the pores of the wood; it is also employed for weighting cotton goods. The bromide and the iodide are both official in the Pharmacopo'i.a, the former being used in the treatment of epilepsy and the latter for scrofula and hysteria. Zinc sulphate, originally known as 'white vitriol,' and found native as goslarite, was described by Basil Valentine. This salt may be obtained by roasting ores containing zinc sul- phate, afterwards exhausting with water, and then evaporating to crystallization. It is a white powder used in medicine as an astringent ; it is also used in dyeing and calico printing, in the manufacture of varnishes and drying oils, for painting, and for the preparation of zinc-white and other zinc compounds. ilET.LLURGY OF ZiNc. Zinc may be extracted from ores and furnace products by ( 1 ) the dry process, or (2) the electro-metallurgical process, jietallic zinc can only be obtained in the dry way and by electro-metallurgical proces.ses. As zinc cannot be separated from its solutions by any of the metals that resist ordinary tempera- tures, the wet method only admits of the produc- tion of compounds of zinc from which the metal must be extracted in the dry w^ay. The wet process can, therefore, be considered only as an accessory process to the dry method of zinc ex- traction. The extraction of zinc from ores and furnace products in the dry way is performed by converting the zinc into an oxide and then re- ducing the oxide to a metal by means of carbon. Furnace pro<lucts which consist of mixtures of zinc oxide and metal are submitted to direct reduction. From alloys with metals less volatile than zinc the latter is obtained by simi)le dis- tillation. The extraction of zinc by the com- bined wet and dry method is performed by dis- solving out the zinc, converting the zinc in solu- tion into an oxide, and then reducing the latter by means of carbon. The electrolytic extracticui of zinc is performed by obtiiining zinc in the form of aipieous solutions, from which zinc is se])arate(l by means of the electric^ current. If the zinc exists in the form of an alloy this alloy may be used as the anode in the electric current. Of the three methods,