September 19, 1901] 



NA TURE 



517 



widespread formation of new lime-soda-felspars from the zeolites 

 in the lavas. 



After the intrusion of the granite of the Red Hills, Mr. Harker 

 finds that igneous activity took the form of intrusions of smaller 

 volume, but in some cases of wide distribution. The great group 

 of dolerite sills belongs to this period. An enormous number of 

 acid and basic dykes followed, of several distinct epochs. A 

 set of minor basic intrusions of quite late date is found in the 

 gabbro district of the Cuillins, the most interesting of which 

 takes the form of .sheets of dolerite, parallel at any given 

 locality, but always dipping towards the centre of the gabbro 

 area. Mr. Harker considers that this remarkable system of 

 injections presents a new problem in the mechanics of igneous 

 intrusion. The latest phase of vulcanicity in the Cuillin district 

 is a radial group of peridotite dykes. As regards the local group 

 of rock in Central Skye Mr. Harker finds that the order of 

 increasing acidity which ruled in the plutonic phase was reversed 

 for the minor intrusions which followed. 



In connection with the great development of volcanic activity 

 in the West of Scotland in Tertiary time reference must be made 

 to the remarkable volcanic vent in Arran the recognition of 

 which is due to the suggestion of my friend Mr. Peach. This 

 volcanic centre covers an area of about eight square miles, and 

 lies to the south of the granite area of the island (Quart, louni. 

 Geol. Soc, vol. Ivii. p. 226 {1901). The vent is now filled with 

 volcanic agglomerate and large masses of sedimentary material, 

 some of which have yielded the Rha:tic and Lower Lias fossils 

 already referred to, the whole being pierced by acid and basic 

 igneous rocks. One of the interesting features connected with 

 it is the occurrence of fragments of limestone with the agglo- 

 merate, which has yielded fossils of the age of the chalk, thus 

 proving that the vent is post-Cretaceous. There is thus strong 

 evidence for referring the granite mass in the north of the island 

 and most of the intrusive, acid, and basic igneous rocks to the 

 Tertiary period. It furnishes remarkable proof of the suggestion 

 of the Tertiary age of the Arran granite made by Sir A. Geikie 

 in 1S73 (Trans. Geol. Soc. Edin., vol. ii. p. 305). The story 

 unfolded by this discovery is like a geological romance. The 

 former extension of Rhoitic and Lower Lias strata and of the 

 chalk in the basin of the Clyde, and the evidence of extensive 

 denudation in the south of Scotland, appeal vividly to the 

 imagination. 



This outHne of the researches in the solid geology of Scotland 

 would be incomplete without reference to the publication of Sir 

 A. Geikie's great work on "The Ancient Volcanoes of Great 

 Britain " {1897), in which the history is given of volcanic action 

 in Scotland from the earliest geological periods down to Tertiary 

 time. To investigators it has proved invaluable for reference. 

 Nor can I omit to mention the new edition of his volume on 

 "The Scenery of Scotland," wherein he depicts the evolution 

 of the topography of the country with increasing force and 

 fascination. In this domain it may be said of the author, 

 "Nihil tetigit, quod non ornavit." 



From the brief and imperfect sketch which I have tried to 

 give of recent advances in the solid geology of Scotland it will 

 be admitted that restless activity and progress have been 

 characteristic of the last quarter of a century. But we may 

 expect that the conclusions accepted now will be rigorously 

 tested by our successors, probably in the light of new discoveries 

 and with more perfect methods of research. It is well that it 

 should be so, for thereby our branch of science advances. 

 Meanwhile, as we look back on the phalanx of geologists that 

 Scotland has produced — to Hutton and Hall, Murchison and 

 Lyell, Hugh Miller and Fleming, Nicol and Ramsay — and 

 reflect on the services which they rendered to geology, we may 

 hope that this record of progress may prove a fitting sequel to 

 the labours of these illustrious men. 



SECTION G. 



.MECHANICS. 



Opening Address by Colonel E. E. Cro.mpton, 

 M. Inst.C. E. , President of the Section. 



At this the first meeting of the British Association of the new 

 century I wish to lay before you some of the interesting problems 

 presented by recent developments in means of locomotion on 

 land which demand the best thoughts, not only of our engineers, 

 but of everyone interested in the improvement in means of 

 travelling and in the more rapid transit of goods. 



NO. 1664, VOL. 64] 



During the seventy years which have passed since the intro- 

 duction of railways in almost every country, passenger and goods 

 traffic has developed itself to such an extent that almost every- 

 one is interested in these questions ; and of late years our atten- 

 tion has not been confined to railways only, but, owing to the 

 invention of the cycle and motor-car, has also been directed to 

 travel on our road-ways, which during the first fifty years of the 

 railway era had somewhat fallen into disuse. I am not able, 

 being limited to the length of this address, to deal with many 

 of the interesting questions affecting our long-distance r.ailways 

 other than by referring to the probable early introduction of 

 railways of a new type intended to attain a speed of 120 miles 

 per hour and worked by electrical power. The railway race to 

 Scotland of a few years back attracted the attention of the 

 managers o( American and Continental railways to railway 

 speed questions, and we have seen during the last few years so 

 great improvement in the speed of the trains and the comfort of 

 the passengers in these countries that it appears that England 

 has already been beaten in the matter of extreme railway speed, 

 although it is probable that our railways still provide a larger 

 number of rapid trains than either the American, German, or 

 French do. But whether it be in England or in the countries 

 I have mentioned, it appears that after all the speed limit of 

 railways of the present system of construction is reached at 

 about sixty-five or seventy miles per hour. Higher speed on 

 level runs has undoubtedly been recorded, but it is not probable 

 that anything greatly in excess of .seventy miles per hour will be 

 reached until our railway managers initiate an entirely new 

 system of construction. The high-speed service that is now in 

 contemplation, not only in England but in America and Germany, 

 intends to attain speeds Of more than one hundred miles per hour 

 by providing electrical means of haulage sufficient to propel light 

 trains consisting of one, or, at the most, a few cars ; and in 

 order to render this service successful to run these light trains 

 at short intervals of time, so in effecting this high speed the rail- 

 ways will give a service which more nearly resembles the tram- 

 way service than our present system of heavy express trains at 

 infrequent intervals. This high-speed service of light trains at 

 frequent intervals is well suited to electrical haulage, as it works 

 generating machinery situated at fixed points to the best advan- 

 tage and enables the best return to be obtained from the neces- 

 sarily heavy capital cost of copper in the conductors which 

 transmit the energy along the length of the line, as it is evident 

 that if the speed be sufficient to ensure that each section of the 

 line only carries oiie running train, the costs of the conductors 

 will be in proportion to the weight of that train. 



Great advantages have already been made in adapting electrical 

 traction to long lengths of railways. The work already done by 

 Brown Boveri, of Baden, in Switzerland, at first on the mountain 

 railways and afterwards on the Burghdorf-Thun full-gauge line, 

 the experimental work of Ganz and Co., of Buda-Pesth, and of 

 Siemens and Halske at Charlottenburg, have already shown 

 that the power problems are nearly all of them solved, so that 

 we may feel confident that electrical engineers will very shortly 

 surmount any power difficulties that still remain. But this high- 

 speed railways problem at present presents certain unknown 

 factors which can only be satisfactoiily determined by the actual 

 testing and working the lines when carrying passengers. I refer 

 to those which deal with the increased oscillation, vibration, and 

 noise to be expected from the extreme speeds. These matters 

 must be met so as to give sufficient comfort and protection to 

 the passengers, for if passengers are rendered uncomfortable by 

 the extreme speed the service can never become popular, and 

 on this last question depends the most important question of all, 

 viz. the extent to which the travelling public are likely to make 

 use of a high-speed railway service. In attempting to forecast 

 this matter, although we meet many business men who think it 

 would be an undoubted advantage if the journeys between im- 

 portant business centres occupied half the time they do at 

 present, in the United Kingdom there are only a few journeys 

 of sufticient length to make saving of time nf great importance, 

 but the case is far different in America and on the Continent, 

 where the business centres are much further apart than they are 

 here. I, as an English engineer, foresee that this topographical 

 question will cause our English engineers to be at a disadvan- 

 tage as compared with .\merican and Continental ones, for it 

 appears likely that the number and mileage of high-speed rail- 

 ways is likely to be far greater in .America and on the Continent 

 than in the United Kingdom. Before I entirely leave the subject 

 of very high-speed railways, a rather curious speculation presents 



