1873 •] Geology. 269 



to the height of the Nile and weight of the vessel. Thence the river commu- 

 nication will extend to Wady Haifa, the commencement of the Soudan 

 Railway. A transference from steamboats to railway will take place at this 

 point, and the 560 miles of the Soudan Railway will extend to Skendy. From 

 Skendy to Massowah, the port on the Red Sea where the sea-passage will be 

 again resumed, is 430 miles, which will be accomplished by an extension of 

 the Soudan Railway. The gauge fixed on for the railway is 3 feet 6 inches. 



Rail Economy. — In December last a paper, by C. P. Sandberg, was read 

 before the American Society of Civil Engineers, in New York, upon " Rail 

 Economy," in which — under the three heads Iron Rails, Steel Rails, and 

 Traffic Capacity — the author dealt with the saving that might be effected in 

 the item of railway cost. It was remarked that the late increased expense of 

 iron added to the cost of railway construction, and tended to reduce the 

 quality of rails ; that Welsh rails were now often inferior in quality, but in 

 the Cleveland district rail-making had greatly improved, chiefly by the increased 

 application of fettling in the puddling-furnace. No late improvement, it was 

 observed, promised so much to perfect iron rail-making as mechanical pud- 

 dling, which now seemed to be an entire success. The demand for steel rails 

 has become so great that they can now hardly be obtained at any price, whilst 

 the supply is also limited by the lack of ore free from sulphur and phosphorus. 

 The Siemens-Martin process of steel-making is declared to be superior to the 

 Bessemer process, as it requires a less pure ore, but it has thus far proceeded 

 so little that it can hardly be called a source of supply in the great market. 

 Usually a steel rail will carry one-fifth more dead load than an iron one ; 

 hence, for the same traffic, the steel rail, in comparison with the iron, should 

 not be reduced in weight more than 20 per cent. The weight passed over 

 good iron rails, before rejection, has been found to average 10,000,000 tons, 

 which may be taken to represent the life of extra iron rails, and six times that 

 the life of good 56-lb. steel rails. On the London and North-Western line 

 steel rails have lasted twenty times as long as iron ; and on the Metropolitan 

 Railway, with the greatest traffic in the world, where iron would not have 

 lasted six months, steel will stand from three to four years. Prof. Rankine 

 says the weight of the rails per yard in length should equal fifteen times the 

 greatest load on the locomotive-drivers in tons. Perdonnet, in France, takes 

 twelve in place of fifteen. The author of the paper, by adopting a section 

 which permits a fish-joint stronger than the others in general use to be 

 made, takes ten and less ; thus for a 6o-lb. rail the weight on drivers is put at 

 6\ tons. Fish-plates of steel will enable rails to carry from 15 to 20 per cent 

 greater load than if iron were used of the same section. 



GEOLOGY. 



Obituary. — The Rev. Adam Sedgwick. — Geological science has expanded so 

 much during the past fifty years that it is difficult for any one man to be master 

 of all the subjects it embraces. Sir Charles Lyell has expressed the difficulty 

 he has felt from year to year in keeping up with its progress, and no man has 

 done more to further the advancement of geology than he. by presenting the 

 principles and general results of the science before the public. We have very 

 few of those veteran geologists left who connect, as it were, the early history 

 of geology with its present advanced state, who have contributed most largely 

 to lay the foundations (which are lasting monuments to their honour) to 

 which the geologists of the present day are adding detailed work — and there is 

 plenty of that to be done. 



The Rev. Adam Sedgwick, who died on the 27th of January last, at the ad- 

 vanced age of 87, was one of those veterans who helped to lay the foundations 

 of geological science, and who is therefore intimately connected with its 

 progress. Although for some years past he took no very active part in the 

 furthering of geology, he yet remained until death at his post of Professor of 

 Geology in the University of Cambridge, which post he had held since the 

 year 1818, when he succeeded Professor Hailstone. 



At this period little was known in England of geological science, but a 



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