258 



ENGINEERING. 



H. R. Robinson, of Nova Scotia, made a sec- 

 ond attempt, which proved successful, in No- 

 vember, 1887. The raft was 560 feet long, 50 

 feet wide, 35 feet deep, and cigar-shaped, as 

 shown in the engraving. A heavy chain- 

 cable ran longitudinally from end to end at the 

 center of the mass, and to this flexible back- 

 bone were attached other chains at intervals of 

 ten feet, binding the whole together in a solid, 

 yet more or less elastic mass. Other chains 

 were tightened around the outside, and the 

 swelling of the logs when immersed was count- 

 ed upon still further to stiffen the whole. No 

 fewer than 25,000 logs were thus lashed togeth- 

 er upon launching- ways constructed with the 

 greatest possible strength. In weight the raft 

 largely exceeded any vessel that has ever been 

 launched, and in size nearly equaled the Great 

 Eastern. Its successful management on the 

 ways is certainly a very creditable feat of en- 

 gineering. The subsequent fate of the raft was 

 not encouraging for a repetition of the experi- 

 ment. The voyage was undertaken in Decem- 

 ber, and in tow of an ocean-steamer the raft 

 was towed through several gales and reached 

 a point near Nantucket shoals, when a gale of 

 such violence was encountered that the cables 

 parted and the steamer abandoned her charge. 

 The United States Government at once dis- 

 patched vessels to remove such a danger to 

 navigation, and in a few days it was ascer- 

 tained that the raft had broken up, covering 

 the sea for miles with its fragments. 



Under this heading should be mentioned the 

 launching of the Trafalgar (12,000 tons dis- 

 placement), the largest iron-clad afloat, and the 

 successful raising of the steamers Welles City 

 and Locksley Hall, the first of which was sunk 

 in the Hudson river opposite New York city, 

 and the other in the river Mersey at Liver- 

 pool. In both cases wire cables were passed 

 under the sunken vessels, and the rise and fall 

 of the tide utilized in raising them to the sur- 

 face, so that they could be towed into shoal 

 water for repairs. 



Railways. A few years ago conservative 

 travelers denounced the railway to the summit 

 of Mount Washington as a desecration of na- 

 ture, and were fond of saying that such out- 

 rages would not be permitted in Europe. 

 Since then similar railways have been con- 

 structed on Mount Rigi and Mount Pilatus in 

 Switzerland, the last named having been com- 

 pleted within the year. It overcomes steeper 

 grades than any other road of its kind, and 

 such is the rugged character of the mountain 

 that excessive precautions had to be taken to 

 guard against the creeping downward of the 

 rails. The steepest grade of this road is 480 

 in 1,000. Among the difficulties to be over- 

 come was the provision against expansion and 

 contraction from changes of temperature, 

 which are often abrupt, and in the course of 

 twenty -four hours may cover many degrees. 



In Russia some of the great government 

 lines are laying double tracks, and the rails are 



steadily pushing on toward the Asiatic fron- 

 tier and across Siberia. German contractors 

 have secured a large proportion of the Japan- 

 ese railways now in course of construction. 



In South America the daring schemes of 

 engineers continue to receive encouragement, 

 and the already elaborate system of railways 

 through different regions is being farther ex- 

 tended. It is singular to find at this day that 

 a tramway 200 miles long, with animals for 

 motive power, is under construction in Buenos 

 Ayres. The explanation is, of course, the ex- 

 pensiveness of machinery and the local cheap- 

 ness of draught-animals. 



Transportation by Rail. The French Govern- 

 ment, having recently met with some disasters 

 in sending torpedo-boats from Toulon to Cher- 

 bourg by sea, decided to make the attempt to 

 send them by rail. Trucks were constructed 

 for the service. Each had three axles seven 

 feet apart, the end axles having Recour bear- 

 ings, which enable it to turn readily on a curve 

 of 375 feet radius. The main platform con- 

 sists of a frame secured to the truck by a main 

 bolt and supported by spherical bearings which 

 rest in guides. On each of the trucks is a 

 large cradle or skid, shaped to correspond 

 with the contour of the boat, and pivoted upon 

 its bed. The two trucks are coupled closely 

 together, forming as it were a single car, with 

 the cradle-pivots about 27 feet apart. To 

 lower the cradles as much as possible the sup- 

 ports are sunk between the wheels, the height 

 of the vessel being, of course, limited by that 

 of the bridges under which it is obliged to 

 pass. The boat selected for the trial was 111 

 feet long, 11 feet wide, and 9 feet deep, and 

 weighed, when stripped for the journey, 38 

 tons. Of course all the removable parts were 

 detached before shipment. The line of the 

 keel corresponded always with a line passing 

 through the cradle-pivots, and considerable 

 deflection had to be provided for, since the 

 bow and stern projected, respectively, 44 feet 

 and 33 feet in front and rear of the cradles. 

 There was some danger that this overhang 

 would cause too great a strain, as the iron ' 

 plates were only three millimetres thick, but 

 the journey of 847 miles was performed with 

 no apparent injury. 



The boat occupied the space of about five 

 ordinary cars. The train was moved at a rate 

 of about sixteen miles an hour, except for an 

 experimental test, when the speed was in- 

 creased to twenty-four miles an hour. It 

 was demonstrated to the satisfaction of the 

 engineers that a boat even larger than the 

 one used could be transported from Toulon to 

 Cherbourg in four days and three nights, and 

 could be ready for service in twenty-four 

 hours after its arrival. This exploit is, be- 

 yond doubt, the most considerable feat of 

 ship-transportation by rail ever undertaken, 

 and it goes far to demonstrate the practicabili- 

 ty of such transportation, under more favor- 

 able conditions, of ships of far greater size. 



