Page:The New International Encyclopædia 1st ed. v. 19.djvu/40

* TANNEK. 24 TANNIN. a valuable account of the authors that flourished in t!ie three kingdoms up to the seventeenth cenluiy (posthumous, 174S). With him An- tony a," Wood (q.v. ) left additional 'lives,' which apjieared in the second edition of Athenw Oxonicnses (1721). Tanner bequeathed a large bodv of manuscripts to the Bodleian Library at O.xf'ord. TANNERY, ta'ne-re', Paul (1843—). A Frcncli scholar, born at Nantes. He was edu- cated in the Paris Polytechnic School ; engaged in the tobacco industry ; and devoted his leisure time to studying the history of science and of philosophy. For two years he gave a course in the Sorbonne on the history of arithmetic, and for five j'ears filled Professor L^vecque's chair in the history of Greek and Latin philosophy in the College of France. Aside from a great num- ber of articles in periodicals and other publi- cations, he published: Pour I'histoire de la science heUene (1887); La gfonnitrie grecque (1887) ; La correspondance de Descartes da7is les inedits des fonds Libri (18n.3); and Recherches sur rhistoire de Vastronomie ancienne. TANNHAXTSER, tiin'hoi-zer. A German knight and minnesinger of the thirteenth century, probably a Bavarian by birth, who enjoyed the favor of Duke Frederick II. of Austria. Little is known historically of his career, and he dis- appears entirely after the death of Conradin (1268). His verses are in the main mocking and sensuous. One of the latest of them, a penitential song, may have led to his identifica- tion with the hero of the old Teutonic legend of the Venusberg or Hill of Venus. This was a region within a mountain near the Wartburg, in the Thuringian Forest, where Venus reigned, and whence no one save Tannhiiuser ever escaped. Here Tannhiiuser, in the legend, lived with her until conscience smote him. He escaped, with the aid of the Blessed Virgin, and set out on a pilgrimage to Rome, to obtain pardon for his grievous sin. According to the story. Pope Urban IV. refused to pardon the sin until the staff in the Pope's hand should sprout. Tann- hiiuser returned to the Venusberg, but the wand meantime put forth green leaves by a miracle, to show the extent of the divine mercy. Modern versions of the legend were made by Tieck, Heine, and Geibel ; and in Swinburne's Lavs Veneris Tannhiiuser is conceived as having returned ir- redeemably to the Venusberg. But better known than any is the famous dramatic treatment by Richard Wagner in his opera Tannhdiiser (1845), whose libretto follows Hofl'niann in identifying Tannhiiuser with Heinrich von Ofterdingen and introducing him into the contest of the minstrels on the Wartburg. The works of the historic Tannhiiuser were first edited by Von dcr Hagen in his Minnesinger (1848). For these consult: Oehlke ( Kiinigsberg, 1800) and Siebert (Berlin, 1894) ; for the legend, Baring-Gould, Curious Myths of the Middle Ages (London, 1884), and Griisse, Der Tannhiiuser und der ewige Jude (2d ed., Dresden, 1890). TANNIN (from tan, OF., Fr. tan, oak-bark for tanning, from OHG. tanna, Gcr. Tanne, fir, oak ; probably connected with Skt. dhanran, bow), Ta.nnic Acid, Gallotannic Acid, or Di- Gallic Acid, C,.H2(0H)3C00C(H„(0H)2C00H. An odorless and almost colorless substance, sol- uble in water, alcohol, acetone, glycerin, and various oils, occurring in Turkish and Chinese gall-nuts and in various other plants. It has a bitter, astringent taste, and assumes a yellow coloration if e.xposed for some time to the action of light. It is used as an astringent in medicine and as a mordant in dyeing, and also finds em- ployment in the manufacture of ink and of gallic and pyrogallic acids. Solutions of tannin reduce . silver carbonate to metallic silver : they also re- duce Fehling's solution (q.v.), and certain other substances, and precipitate gelatin and albumen from their solutions. On the other hand, solu- tions of tannin may be precipitated by the addi- tion of various salts and acids, including common salt, sal ammoniac, the acetate as well as the sul- phate of potassium, hydrochloric and sulphuric acids, etc. Tannin is made by extracting the powdered gall-nuts, which contain it in larger quantities, with a mixture of alcohol, ether and water ; the layer of water then contains practically all the tannin ; it is separated, purified by shaking with an excess of ether, and evaporated at a gentle heat. The residue thus obtained may be purified by dissolving in a dilute solution of common salt, and reprecipitating from this by adding an excess of salt in the solid state. With ferric salts tannin produces the well-known precipitate which is the coloring substance of ordinary black ink. The names tannin and tannic acid are also applied to a variety of other substances of vege- table origin and having properties more or less similar to those of gallotannic acid: they are all astringent, transform hide into leather, give a blue or green coloration with salts of iron, etc. Some of the more important of these substances may be briefly noticed here under their special names. Alder Tannin, C^HaOi,. This is a reddish- brown substance soluble in dilute alcohol and quite soluble in hot water; its solutions give a green precipitate with ferric salts. It may be prepared by extracting sawdust from Almis glutinosa with boiling water, precipitating the extract with lead acetate, and decomposing with sulphureted hydrogen ; the precipitate, which now contains both the tannin and lead sulphide, is extracted with alcohol, and thus the tannin is isolated. Caffetannic Acid, CuHijOs. This is found in cofTee-berries and in certain other vegetable prod- ucts. It is soluble in water and in alcohol and its solutions give a green coloration with ferric salts. It may be prepared by extracting coflfee- berries with alcohol, diluting with water, filter- ing, boiling the filtrate and precipitating it with load acetate: tlie precipitate thus obtained is shaken up with alcohol, in which it is caused to dissolve by decomposing with sulphureted hydrogen, and then the caff'etannic acid is isolat- ed by filtering and evaporating the solution to dryness. Fraxitannic Acid, C^nHj.O,,. This is found in the leaves of the ash-tree. From these it may be obtained by extracting with water, precipitating the extract with lead acetate, and dissolving the precipitate in boiling aqueous acetic acid. The tannin is then isolated by a somewhat elaborate process, involving tractional precipitation with ammonia, treatment of the purest fractions with sulphureted hydrogen, etc. (Consult Monats-