l82 



NATURE 



{July 9, 1874 



countries, except probably at points where the distance 

 presents apparently insuperable difficulties. The lower 

 chalk or chalk marl affords a comparatively impermeable 

 deposit, also of sufficient dimensions : but from its having 

 a calcareous base, and from the possibility of fissures, 

 with the absence of a protecting overlie, it has great un- 

 certainty. In the gault there is another impermeable 

 stratum, but of dimensions too small. The lower green- 

 sand contains no beds sufficiently continuous and imper- 

 meable. The Weald clay ranges about half-way across 

 the channel ; and if a belt of it should possibly pass 

 round at the north end of the Varne and range to Wissant, 

 it might prove to be worth further inquiries. In the 

 Kimmeridge clay there is again a deposit of sufficient 

 dimensions, but with a subordinate band which may be 

 sufficiently permeable to present difficulties, whilst, though 

 it comes to the surface on the French coast, its depth on 

 the English coast must be very considerable. There is, 

 however, just a chance that the Kimmeridge clay may in 

 mid-channel be overlapped unconformably, and at a slight 

 angle, by the Weald clay, and in that case they might 

 for all purposes be considered as continuous strata. The 

 Oxford clay presents similar difficulties, in addition to its 

 greater depth and inaccessibility. In the secondary strata 

 the irregular lie of the strata, and the presence of faults, 

 are contingencies important to be considered. 



" On the other hand, the great mass of the Pateozoic 

 rocks so protected by impermeable overlying strata, is of 

 such great dimensions, and so compact, and holds its 

 range so independently of the more irregular range of the 

 secondary strata, that it offers the conditions most favour- 

 able for the secure construction of a submarine tunnel ; 

 and that such strata can be worked in safety and for con- 

 siderable distances under great bodies of water, has been 

 proved at Whitehaven and Mons. But, on the other 

 hand, the depths of these old rocks below the surface is 

 very great, and they are much more dense and harder 

 than the overlying formations. 



" There is another important problem in connection with 

 the Palaeozoic rocks which such an undertaking might 

 help to solve. The great question of the range of the coal 

 measures under the south of England has lately come 

 prominently into notice ; and it was, in fact, in inquiries 

 connected with that question that the foregoing considera- 

 tions presented themselves to the author. The rich coal 

 basin of Mons and the north of France has been traced 

 to within thirty miles of Calais, where it thins out ; but, 

 like the coal basins of Liege, Aix, and Westphalia, which 

 form separate sections of the same great trough, to the 

 eastward, so there is reason to suppose that other sec- 

 tions of the trough set in on the westward, forming other 

 coal basins, which possibly range to the west of England 

 (Somersetshire), passing under the north-eastern part of 

 Kent and the Thames. Any such work, therefore, as a 

 submarine tunnel in these Pateozoic rocks could not fail 

 to throw much light on the subject ; while, in case it were 

 to hit upon the line of strike of the coal measures, and 

 could be carried on along that line, the work might prove 

 otherwise remunerative, and tend to solve the great , 

 problem which interests so largely both geologists and 

 the general public. 



" Such, briefly, are the conditions which bear on the 

 construction of a submarine tunnel between France and 

 England. The author is satisfied that, considered on 

 geological grounds alone, it is in one case perfectly prac- 

 ticable, and in one or two others it is possibly so ; but 

 there are other considerations besides those of a geologi- 

 cal nature, and whether or not they admit of so favour- 

 able a solution is questionable. In any case the author 

 would suggest that, the one favourable solution admitted, 

 it may be desirable, in a question involving so many and 

 such great interests, not to accept an adverse verdict with- 

 out giving all those other considerations the attention and 

 delilseration which the importance of the subject deserves. 



" Under any circumstances, the difficulties are formid- 

 able. Whether or not they are insuperable are questions 

 which may safely be left to Civil Engineers. The many 

 and great obstacles overcome by engineering science in 

 late years lead the author to expect that, should the occa- 

 sion arise, and the attempt be considered worth the cost, 

 the ability to carry it out would not be wanting. Various 

 preliminary trials are, however, indispensable, in order to 

 clear up some of the geological questions before a balance 

 of the comparative advantages presented by the different 

 formations could be satisfactorily settled, and before the 

 grounds for action could be accepted." 



From this it will be seen that the possibility of a 

 Channel Tunnel remains now only with the engineers to 

 decide. Geology has told them all the natural conditions 

 under which they will have to work, so far as these can 

 be known without actually tunnelling ; and since so 

 cautious a reasoner as Mr. Prestwich thinks it possible to 

 carry out the scheme from a geological point of view, we 

 should think that if it could be proved that the under- 

 t.aking would pay, our engineers would be eager to show 

 that the resources of their art are quite equal to its suc- 

 cessful accomplishment. 



OWENS COLLEGE "ESSAYS AND 



ADDRESSES " 



Essays and Addresses. By Professors and Lecturers of 



the Owens College, Manchester. (London: Macraillan 



and Co., 1874.) 

 '"T'HIS book is due to the natural desire of the teaching 

 -L staff of the Owens College to have some memorial 

 of an event of the first importance in their own history, 

 and to give expression to the hopes that animate the 

 institution. The Owens College was founded by a single 

 legacy a quarter of a century ago^for the creation of a 

 college in which Lancashire lads might study at home the 

 " branches of learning commonly taught in the English 

 Universities." It first became known in connection with 

 its first Principal, Scott, a writer who has left nothing 

 which explains the high rank he held among his contem- 

 poraries and especially the influence he unquestionably 

 exercised over every young man with whom he was 

 brought into contact. Under him, however, the College 

 did not flourish — the number of the day students sank at 

 one time as low as 25 — and it was only after the appoint- 

 ment of the present Principal, Dr. Greenwood, that it 

 began to take root in Manchester. It has now about 350 

 day students — not including the medical students, who 

 have been added only this session — and nearly 800 

 evening students. Curiously enough, what happened in 

 Glasgow to the disappointment of many of the well- 

 wishers of the University, happened also in Manchester. 

 When the new buildings, with all their increased conveni- 

 ence for study, were opened, it seemed natural to antici- 

 pate a great increase of students. Nothing of the kind 

 took place. Students seem to come and go to college 

 because they want to be taught, not because they are to 

 have beautiful buildings to be taught in. The eftect will 

 certainly be considerable, alike on teachers and on taught, 

 of the more commodious buildings recently erected in 

 Glasgow and in Manchester, and it will be felt more and 

 more as time goes on. The fact that it is not felt at first 

 shows, however, that the wants that are satisfied by univer- 



