April 19, 1900] 



NATURE 



595 



As regards safety, the collieries of the United Kingdom occupy 

 a high place compared with those of the rest of the world. 

 Prof. Foster sounds a note of warning to British mine-owners 

 and points out that the parasitic disease known as ankylo- 

 stomiasis is attracting the special attention of several foreign 

 Governments, owing to the ravages which it is committing 

 among colliers. From inquiries he has made among his col- 

 leagues, it appears that the disease is not known among British 

 colliers ; but as it has made itself a home in coal mines in 

 Northern Europe, it might be introduced into this country by 

 foreign workmen. 



Two interesting papers on changes in iron and steel rails 

 were read at the meeting of the Institution of Civil Engineers 

 on April lo. In the first of these, on *' The development of 

 the manufacture and use of rails in Great Britain," Sir Isaac 

 Lowthian Bell, Bart., F.R.S., traced the history of the develop- 

 ment of wrought-iron and steel manufacture, with particular 

 reference to its employment for rolling into rails. The results 

 of an experimental investigation of the deflection of rails at 

 various speeds of the train, indicate that the deflection, and 

 therefore the pressure on the rail, diminishes as the speed in- 

 creases. The durability of rails manufactured by the basic 

 process has proved equal to that of steel rails manufactured from 

 hicmatite ore. In the second paper, on " The wear of steel 

 rails in tunnels," by Mr. Thomas Andrews, F.R.S., the effects 

 of the deteriorating influences peculiar to rails laid in tunnels 

 were described. Among these are the increased corrosion of 

 the surface of the rail, due to the action of moist vapours, and 

 the increased chemical action of the ballast on the foot of the 

 rail ; the ballast, on account of its porous nature, absorbs the 

 vapours and hence acts with increased deteriorative force on the 

 rails. Mr. Andrews has made a careful examination of a rail 

 which did its life's work in such a situation. The rail was laid 

 in a tunnel for seven years, on a straight piece of road having a 

 falling gradient of i in 90, and it carried the main-line traffic 

 during this time without fracture. The tunnel was about \QOO 

 yards in length, and it was situated fairly near the sea-coast. It 

 lay in a direction nearly north and south. This fact was pointed 

 out, as Mr. Andrews has observed indications that magnetisa- 

 tion exerts an influence tending to increase the corrosibility of 

 steel in certain solutions The rail, which originally weighed 

 84 lbs. per yard, had lost weight at the rate of 28 lbs. per yard 

 per annum, and on the face the rail had worn down to the 

 extent of |-inch. The chemical analysis showed that sulphur 

 was present in considerable excess, but otherwise the general 

 composition of the steel was excellent. The physical tests 

 showed a very good result, the strength of the metal being 

 normal, and an elongation of 27 per cent, being obtained. From 

 the results of the investigations, the conclusion was arrived at 

 that, as a general rule, rails in tunnels should only be allowed 

 to remain in the permanent way for one-half (or in some cases 

 only one-third) of the time that is usually allowed for the 

 ordinary use outside tunnels. 



In the American Geologist for last February, Prof. E. W. 

 Claypole gives a brief description of an earthquake felt in 

 southern California at 4 25 a.m. on December 25, 1899. The 

 disturbed area is thinly populated, but the shock was felt for at 

 least 150 miles from the coast. In the two villages of San 

 Jacinto and Hemet, which stand in an elevated valley filled 

 with detritus from the adjoining mountains, every brick build- 

 ing was seriously damaged by the shock. Prof. Claypole 

 remarks that, from the continued occurrence of light tremors, 

 the region would be a good one for making seismological 

 observations. 



An important memoir, by Mr. R. D. Oldham, on the propa- 

 gation of earthquake motion to great distances, has just been 

 published in the Phil. Trans, of the Royal Society. The com- 

 NO. 1590. VOL. 61] 



plete record of a distant earthquake, he remarks, shows three 

 principal phases, differing in character and amount of displace- 

 ment. During the first two phases, the motion is principally of 

 a to-and-fro nature ; while in the third phase, the movement is 

 composed of long surface undulations resembling the swell of 

 the ocean. In the first two phases, the surface-velocity increases 

 with the distance from the origin, and in accordance with the 

 hypothesis that they consist of elastic waves propagated through 

 the earth at rates which increase with the depth below the sur- 

 face. If the time-curves for the beginnings of the first and 

 second phases are continued to the origin, they give initial rates 

 of propagation which agree fairly closely with the probable 

 initial rates of propagation of condensational and distortional 

 waves in continuous rock ; and Mr. Oldham therefore concludes 

 that the first phase represents the arrival of condensational 

 waves, and the second phase of the distortional waves, 

 both having travelled along brachistochronic paths through the 

 earth. In the third phase, the surface- velocity appears to be 

 constant at all distances from the origin, from which we may 

 infer that they are propagated as surface undulations. The 

 velocity is not, however, the same for all earthquakes, but 

 increases with the intensity ; and from this fact, and the high 

 velocity in the case of great earthquakes, it seems probable that 

 the propagation of these waves is, at least in part, gravitational. 



In the Transactions of the Institution of Engineers in Scot- 

 land, Prof. Andrew Jamieson gives an account of his visit to 

 Cape Town last year, undertaken for the purpose of investi- 

 gating the action of electric tramway currents in disturbing the 

 action of the submarine cables landed at the Cape. Prof. 

 Jamieson summarises the various probable actions of the tram- 

 way currents on the cables as arising from (i) electrolysis ; (2) 

 affecting the potential of the earth connection to the receiving 

 instrument ; (3)direct electro-magnetic induction ; (4) disturbances 

 due to leakage or stray return currents from the tramway rails. 

 It would appear probable from the discussion that the influence 

 of earth-resistance is very considerable at the Cape. Prof. 

 Jamieson reported that nothing short of a symmetrically 

 arranged and specially made twin twisted core with double 

 armouring would do for the shore end, and that it would not 

 require to be more than from two to three nauts. It has since 

 been stated that the recently laid shore end of the new cabl 

 from Cape Town to St. Helena has been made and connected 

 in this way. 



Mr. Samuel Cutler, jun., who has given especial 

 attention to the development of the carburetted water gas 

 industry, describes the process of production, and various modern 

 types of plants, in Feilden's Magazine for April. Carburetted 

 water-gas, as its name implies, is water-gas carburetted, or 

 enriched, with extraneous hydro-carbons, usually derived from 

 petroleum distillates. The gas is now manufactured at more 

 than sixty important gasworks in the United Kingdom, and the 

 number of installations is rapidly increasing. As produced at 

 the present time, the gas is as luminous and odorous as coal-gas, 

 and in the United States it is supplied and used in its undiluted 

 state, though it contains a much larger proportion of carbon 

 dioxide than exists in coal-gas. Here, however, it is chiefly 

 employed to enrich coal-gas. A Department Committee, 

 appointed in 1898, reported in favour of a somewhat stringent 

 limitation of the percentage to be supplied for illuminating 

 purposes, but no legislative measure has yet been based upon 

 the recommendations. 



The present commercial conditions in the vast Chinese Empire, 

 and the possibilities of future development, are described in 

 detail, and from many points of view, in the Monthly Summary of 

 Commerce and Finance of the United States (December 1899), 

 prepared by the Bureau of Statistics. During the short time in 

 which foreigners have been admitted to the commerce of China, 



