tunnel, tunnell

[Old Fr. tonnel (Fr. tonneau) =a tun, a cask, diminutive from tonne a tun (q. v.); cf. Fr. tonnelle a round-topped arbor, an alley with arched top.] I. Ordinary Language: 1. A cask or similar ve el. *2. A funnel (q. v.). "In the midst of complication and intricacy, as evident and certain as is the apparatus of cocks, pipes, tunnels , for transferring the cider from one ve el to another." Paley Nat . Theol ., ch. xv. 3. The shaft of a chimney; a flue, a chimney. "One great chimney whose long tunnel thence The smoak forth threw." Spenser: F. Q., II. ix. 29. 4. A tunnel-net (q. v.). II. Technically : 1. Engin .: A horizontal or slightly inclined gallery beneath the surface of the ground; generally used for an aqueduct or for the pa age of a railway, roadway, or canal. In the construction of railroads it is frequently nece ary to pierce the hills, so as to preserve a line of road as nearly level as practicable. The method of proceeding with tunneling depends mainly upon the kind of material to be excavated. This having been generally ascertained by borings and trial shafts, the work is commenced by sinking the working shafts, which must be sufficiently capacious to admit readily of lowering men and materials, raising the material excavated, fixing pumps, and also for starting the heading of the intended tunnel when the required depth is reached. Besides the trial and working shafts, air-shafts are sunk for the purpose of effect ing ventilation in the works below. Tunnels when not driven through solid rock have usually an arched roof, and are lined with brickwork or ma sonry. The Great Divide Tunnel : A notable engineering feat was accomplished in 1893 in the completion of the boring of the Busk-Ivanhoe railway tunnel under the continental divide of the Rocky Mountains at Hagerman Pa , Colo. The tunnel is almost two miles long-9,393 feet-and is through solid gray granite. It took three years and twenty days, of twenty hours' work each day, to make the excavation. It is 10,800 feet above sea-level, through the top ridge of the continent. The water draining from the one side of the mountain, under which it is driven, runs to the Atlantic Ocean, and from the other to the Pacific. Its construction cost $1.000,000 and twenty human lives. The tunnel substitutes two miles of track for ten, and does away with one of the most expensive railway climbs in the world. 2. Mining: A level pa age driven acro the measures or at right angles to the veins which it is its object to reach. Thus distinguished from the drift or gangway, which is led along the vein when reached by the tunnel. tunnel-borer, s. IMG:content-1554.png:[blocks in formation] Ichthy.: Thynnus thynnus, the best known and most important species of its genus, abundant in the Mediterranean, and ranging to the south coast of England and Tasmania. Body thick, dark blue above, grayish beneath; head large and conical, one-fifth the length of the body; pectoral fin long, reaching nearly to end of dorsal, the spines of which are rather short; tail so widely forked as to be almost crescentic. Specimens ten feet long and weighing 1,000 lbs. have been taken, but fish of half that size are considered large. The flesh, which is pink, is highly esteemed, either fresh or preserved, and the tinned thon mar iné finds a ready sale in countries where the fresh fish is not obtainable. Salted tunny, called sals amentum , was much esteemed by the Romans ( Mart . , X. xlviii. 12). Tunny are usually captured in the Mediterranean in funnel like nets, the fish entering the wide mouth, and being driven to the narrow end, where they are killed with lances and harpoons. The American Tunny, T. secundo - dorsal is , nearly black above, silvery on the sides, white beneath, and somewhat larger than the common species, is found on the coasts of New York and northward to Nova Scotia. It is commercially important, not only as a food fish, but for the oil it yields, twenty gallons being often obtained from a single fish. tup, s. [Prob. akin to top; cf. Low Ger. tuppen, toppen to push, to butt.] A ram. "And it might be a tup's head, for they were in season." -Scott: Rob Roy , ch. xxiv.