Page:The New International Encyclopædia 1st ed. v. 07.djvu/285

* ETHYLENE. 253 ETNA. In the presence of 'platinum black' (finely di- vided platinum), it combines with hydrogen to form the hydrocarbon ethane. Ethylene is formed in the dry distillation of coal, and is therefore one of the constituents of ordinary illuminating gas, to whose flame it imparts con- siderable luminosity. It is prepared in chem- ical laboratories by heating a mixture of strong alcohol ami concentrated sulphuric acid, the alcohol being thus broken up into water and ethylene. Ethylene is one of those carbon compounds that are capable of combining directly with the halo- gens, forming 'additive products'; thus, with bromine it forms the compound C 2 H<Br 2. It is therefore classed with the so-called unsaturated compounds, of which it is the simplest represen- tative. ETIENNE, a'tyen'. See Stepiiam s. ETIENNE DU MONT, a'tyen' du raoN, Saint (Fi, Saint Stephen of the Mount). One of the most beautiful churches of old Paris, founded in 1220 and rebuilt from 1517, but not completed till 102(1. It has a beautiful carved transverse gallery in stone separating the choir from the nave, a feature which is unique in Paris. The church contains the shrine of Saint Gene- vieve, dating from the thirteenth century, and is the burial-place of Pascal and Racine. ETTOLA'TION (from Fr. itioler, to blanch, OFr. estioler, from esteule, stubble, from Lat. stipula, straw). The change in the appearance .■mil structure of a plant caused by its growth in darkness. Lankness and pallor are the most noticeable differences from the normal. Pallor is a relatively superficial effect, and is due to the destruction or non-production of chlorophyll, the chloroplasts showing only a yellow pigment (etiolin), possibly one of the carotin group. Elongation of the stems and leafstalks, imper- fect development of the blades, often a change in the mode of branching, and extensive internal modification of the tissues are more profound effects of absence-of light. The mechanical tis- sues are particularly affected; the cell-walls. which normally thicken, remain thin, and the parts are consequently weak. The "lodging' of grain is often due to the shading of the stalks (on account of thick sowing), so that the mechanical tissues are not developed to a suffi- cient degree to carry the ripening heads. This effect is sought in celery by blanching, the ten- derness of the leafstalks depending upon the completeness with which the cell-walls aie pre- vented from thickening with age. See Carotin. ET'IOLIN (from Fr. dtioler, to blanch). The pale-yellow pigment formed in the chloroplasts of a plant grown in darkness, or remaining after the destruction of chlorophyll by darkness. The relation of etiolin to carotin (xanthophyll) is not satisfactorily determined. It may be one of this group of pigments. It has been shown that the making of a small amount of carbohydrate food is possible through the presence of etiolin in chloroplasts. It seems uncertain and even un- likely that chlorophyll originates by the altera- tion of etiolin. See Etiolation; Photostn- THESIS. ETIQUETTE, et'I-ket (OF. estiquette, eti- qui it'-. Fr. etiquette, from OHG. stehhan, Ger. Btechen, to stick). Originally, etiquette signified a slip of paper affixed to a bog or other object to indicate its contents. The word came prob- ably tn possess the secondary meaning which we mm attach to it, of the forms or decorums ob- served in the intercourse of life, more par ticularly on state occasions, from its having bet n customary to deliver such tickets, instructing each person who was to share in a ceremony as to the part which he was expected to play. The cards on which the order of the dances is set forth at balls and evening parties are of this nature. ETIQUETTE, a'ti'-'kiM'. MADAME. The popu- lar name applied to the Duchess de Noailles fr her rigid application of formalities as mis tress of ceremonies at Marie Antoinette's Court. ETIVE, ct'iv. A sea-loch in the uorth of Argyllshire, Scotland, running inland from the Firth of Lome (Map: Scotland, C 3). The river Vwe, the outlet of Loch Awe, and the small Liver Etive flow into if. The Inch abounds in salmon. The scenery around the upper half of the loch is mountainous and romantic. The ruins of Ard- chattan Priory and of Dunstaffnage Castle add to its interest. ET1AK, Carit. See Brosboll, Joiian Cabi Christian. ET'NA, or MONGIBELLO, mon'je-bel'lo (Lat. .Etna)- The largest active volcano in Europe. It is an isolated mountain on the east- ern coast of Sicily near the city- of Catania- It is cut off from the surrounding mountains on the north by the valley of the Alcantara and on the south and southwest by the valley of the Simento. Its eastern side rises directly from the Mediterranean, which here has a depth of 5000 to 0000 feet. The base of tile volcano meas ures about 90 miles in circumference. The as- cent, gradual at first, leads with increasing slope to the summit, about 10.800 (according to a recent measurement, 10.738) feet above the sea. The general appearance of Etna is that of a massive lava cone, whose regularity of out- line is broken by fissures and by numerous subsidiary cones. Of the latter there are more than 200 located at irregular intervals on the mountain-sides, some reaching a height of 700 feet. The cone occupied by the present principal crater rests upon a terrace which marks the site of an ancient larger cone that was probably de- stroyed by an explosion. On the eastern slope is a vast amphitheatre called the Val del Bove, with precipitous sides nearly 3000 feet high, which was once the centre of eruption and which affords a remarkable view of the volcano's structure and its development during the repeated eruptions. The summit of Etna, except where covered with snow, presents a dreary waste of dark lava. scoria and ashes. Lower down there is a stretch of wooded region with pine, oak, beech, and poplar. A varying breadth of two to eleven miles of cultivated region surrounds its base, producing grain, oil, wine, fruit, and aromatic herbs. Snow persists throughout the year in the fissures of the summits, and on the exposed portions for about eight months. An observatory and a house for the convenience of travelers have been erected on the terrace just beneath the crater. The eruptions of Etna are on a grander scale than those of Vesuvius, but they are not of so frequent occurrence. There arc records of eleven eruptions previous to the Christian Era. the first occurring in B.C. 470 or 477. The most remark-