i8 7 i.] 



Engineering. 395 



diameter at the base, and tapering to 7 feet in diameter at the top. The ver- 

 tical joints are formed internally of T irons, which are continuous from top to 

 bottom, and are rivetted through to outside vertical strips. For the horizontal 

 joints the ends of the cylinders are planed, the joints being butt-joints with 

 strips inside and out. The cylinders are filled in with cement concrete, and 

 finished with stone caps, which form the bases on which the bed girders rest, 

 the caps being placed directly on the concrete. The bottom lengths of the 

 cylinders are held down to the rock by eight bolts let head-downwards into 

 holes drilled in the rock, which are afterwards filled in with Portland cement. 

 Each pair of columns which form one pier are connected at the top by 

 two transverse bed girders, on which the main girders rest on chairs. The 

 main girders are on the Warren principle, each 103 feet long, and have a ver- 

 tical depth of g feet 11 inches from centre to centre of pins. These girders are 

 each fixed at one of their ends over alternate piers, the other ends being free to 

 move on Bessemer steel rollers. The total weight of the ironwork in the 

 superstructure of the Kistnah Viaduct is 2500 tons, whilst that in the cylinders 

 is 1200 tons. 



The Czernowitz Bridge crosses the river Pruth at the town of Czernowitz, 

 the capital of the district of Bukowina, which forms the easternmost portion 

 of the Austrian dominions. The bridge carries a roadway and two side foot- 

 paths, and measures 762 feet 6 inches in length, and 25 feet in width 

 from centre to centre of girders. It has six openings over the river, each 126 

 feet between centres of piers ; the five piers and two abutments are of 

 masonry, resting on concrete foundations. The main girders are continuous, 

 of the single lattice type, and are 11 feet 10 inches deep. The flanges are 

 boxes composed of two large channel irons and a flange plate which connects 

 them. The diagonals are placed at an angle of 45 , and consist of a 

 pair of flat bars which form the ties, and a pair of channel irons braced 

 together, which form the struts. Except at the piers, the main girders 

 have no verticals, nor are they anywhere braced across the top flanges. The 

 method adopted in order to prevent the top flanges from collapsing has been 

 to carry them at every pier in two strong U-shaped frames, which keep the 

 top flanges steady at this point, whilst the stiffness of the flanges between the 

 piers is secured by their great width. The two main girders rest upon roller 

 bearings at each of the piers except the centre one, so that any expansion 

 from increase of temperature radiates outwards from the centre, and extends 

 the bridge equally at each end. The roadway of the bridge consists of a 

 timber platform carried on the cross girders, and supporting longitudinal 

 timbers, upon which is laid transversely 4^-inch planking, and upon this again 

 rest oak blocks 5 inches thick. The footpath is laid with 3-inch oak longitu- 

 dinal decking, upon which the wearing planks are spiked. 



Gas Engineering — Cleland's Steam Jet Gas Exhauster. — At a recent meeting 

 of the Liverpool Polytechnic Society, Mr. William Cleland, Manager of 

 the Lindere Gas Works, read a paper descriptive of the system of exhausting 

 and washing gas by steam which he has adopted. This invention is named 

 the direct action method of exhausting and washing gas by steam, because 

 it aims at superseding in these operations the use of steam engines, 

 and of exhausting and pumping machinery, by bringing the steam into 

 actual contact with its work. The retorts used in the destructive dis- 

 tillation of coal and cannel being made either of coarse fire-clay or of 

 iron, and both kinds becoming very leaky by use, there would thus be a 

 serious loss of gas, if means were not used to prevent it. One of these 

 means is exhausting, pumping, or sucking the gas from the retorts. It 

 is well known that a current or stream of any fluid, moving through any fluid 

 medium, produces, or tends to produce, around itself a current in the 

 fluid medium. For instance, if we blow from the mouth through a small tube 

 which projects into a larger tube open at both ends, the interior stream 

 of breath sets in motion the whole body of air in the outer tube, causing at the 

 further end a copious outflow, and at the near end an inflow. This effect has 

 been termed lateral induction. The outer current is named the induced 



