1026 



TUBES 



right, called the funnel, which terminate above in a water-cistern a, and below in a 

 close basin under c, called the tub or drum. The conical part p of the funnel has 

 been called itranguillon, being strangled, as it wore, in order that the water discharged 

 into the body of the trompe shall not fill the pipe in falling, but be divided into many 

 streamlets. Below this narrow part, holes, q q, are perforated obliquely through the 

 substance of the trompe, called the vent-holes or nostrils, for admitting the air, which 

 the water carries with it in its descent. The air afterwards parts from the water, by 

 dashing upon a cast-iron slab, placed in the drum upon the pedestal d. An aperture, 

 at the bottom of the drum, allows the water to flow away after its fall ; but to prevent 

 the air from escaping along with it, the water as it issues is received in a chest, 

 I m o n, divided into two parts by a vertical side-plate between m n. By raising or 

 lowering this plate, the water maybe maintained at any desired level within the drum, 

 so as to give the included air any determinate degree of pressure. The superfluous 

 water then flows off by the hole o. See ASPIRATOR. 



The air-pipe ef,fig. 2021, is fitted to the upper part of the drum: it is divided, by 

 the point /', into three tubes, of which the principal one is destined for the furnace of 

 cupellation, whilst the other two, gg, serve, for different melting furnaces. Each of 

 these tubes ends in a leathern pocket, and an iron nose-pipe, Jc, adjusted in the tuyere 

 of the furnace. At Pesy, and in the whole of Savoy, a floodgate is fitted into the 

 upper cistern, a, to regulate the admission of water into the trompe ; but in Carniola 

 the funnel is closed with a wooden plug, suspended to a cord, which goes round a 

 pulley mounted upon a horizontal axis, as shown in fig. 2020. By the plug a being 

 raised more or less, merely the quantity of water required for the operation is admitted. 

 The plug is pierced lengthwise with an oblique hole, c c, in which the small tube c is 

 inserted, with its top some way above the water level, through which air may be ad- 

 mitted into the heart of the column descending into the trompe p q. 



The ordinary height of the trompe apparatus is about 26 or 27 feet to the upper level 

 of the water-cistern ; its total length is 11 meters (36-i feet), and its width 2 feet, to 

 give room for the drums. It is situated 10 meters (33^ feet) from the melting furnace. 

 This is the case at the smelting works of Jauerberg, in Upper Carniola. 

 TROXTA.. A name given by the Africans to NATRON. 



TROUBLES. Disturbances in the strata, interfering with the progress of work 

 in a coal mine. 



TRTTFFKBS. A mushroom-like vegetable production, found underground in 

 Northamptonshire and elsewhere, but imported as a luxury from Italy. 



TUBES. The manufacture of iron tubes for gas, water, and other purposes has 

 become one of extreme importance. Mr. Eussell, of Wednesbury, patented a process 

 which has been carried out on a very large scale. In this process plate-iron, previously 

 rolled to a proper thickness, is cut into such strips or lengths as may be desirable, 

 and in breadth corresponding with the width of the tube intended to be formed. 



The sides of the metal are then 

 bent up with swages in the usual 

 way, so as to bring the two edges 

 as close as possible together. The 

 iron thus bent is then placed in 

 an air or blast furnace, and 

 brought to a welding heat, in 

 which state it is withdrawn and 

 placed under the hammer. Fig. 

 2022, A, is the anvil having a 

 block or bolster, with a groove 

 suited to and corresponding with a 

 similar groove B, in the face of the 

 block, c is a wheel with projecting 

 knobs, which, striking in succes- 

 sion upon the iron-shod end of the 

 hammer-shaft, causes it to strike 

 rapidly on the tube. In this pro- 

 cess the tube is repeatedly heated 

 and hammered, until the welding 

 is complete from end to end. A 

 mandril may bo inserted or not during the operation. When the edges of iron have 

 been thus thoroughly united, the tube is again heated in a furnace, and then passed 

 through a pair of grooved rollers similar to those used in the production of rods. fig. 

 2022. Suppose a* tube D, to be passing through these rollers, of which fig. 20215 

 nts a crose-section, immediately upon its being delivered from the groove it 

 receives an egg-shaped core of metal fixed upon the extremity of the rod E. over 



2022 



