December 19, 1907 J 



NA TURE 



16- 



ment is to obtain more extended daylight. Tliis, liow- 

 ever, is not to be wondered at, since the quest of daylight 

 is itself only a part of the greater problem of food supply. 

 .\nv condition, local or other, which tends to restrict food 

 supply in a particular area must produce migration from 

 that area into more favoured areas. This is alone 

 sufficient to account for the winter migrations which many 

 birds exhibit, sometimes to a large extent, and for the 

 localised migrations which some species, not usually re- 

 garded as migrants, exhibit in spring and autumn, moving 

 from one area into another, not necessarily in a different 

 latitude, although often of a different altitude. Further, 

 it must be borne in mind that some birds, and those not 

 few in number, find both sufficient food and sufficient 

 daylight to acquire it in the same region all the year 

 round, and e.xhibit no tendency to migrate. This can in 

 no w'ay be employed as an objection to the view that the 

 true north-south migrants have been driven to seek more 

 extended daylight for the purposes of obtaining a 

 sufficiency of food ; it would equally apply to any other 

 explanation thaf might be given to account for the 

 migratory tendency, and could only be used to prove that 

 there is no necessity for any migration at all, which, as 

 Euclid would say, is absurd. Given a food supply adequate 

 in nature and amount to maintain the species in any 

 region, and sufficient light all the year round to procure 

 it, there would be no need for migration. 



But these are not, and never have been, conditions 

 which obtain in all regions and for all species. On the 

 contrary, a very large number of species appear to require 

 the prolonged daylight of the northern summer to procure 

 a sufficiency of food for themselves and their offspring, 

 while, apart from severity of climate, the shortened hours 

 or absence of daylight which supervene there necessitate 

 that they should pass the winter months in southern lati- 

 tudes. Thus we can comprehend how the north-south 

 migratory instinct became evolved, and we no longer 

 wonder at the existence of this phase of the phenomenon. 

 That ihe great east-west migrations are more complex and 

 more difficult of explanation I ain free to admit, but it 

 must not be forgotten that we know, on the whole, les» 

 about these, and especially less about the climatic and 

 other conditions which accompany them and may be sup 

 posed to produce or influence them, than we do about the 

 influences to which the north-south migrants are exposed. 

 The fact that we are not in a position to solve the whole 

 of a complicated problem need not prevent our attempting 

 to deal with any part for which our existing knowledge 

 enables us to devise an explanation. If I have approached 

 the question entirely from a physiological aspect, it is 

 because it is in the main a physiological question. Never- 

 theless, no physiologist has hitherto attempted to deal with 

 the subject, and it is only with diffidence that I encroach 

 upon a domain which the morphologlst has up to the 

 present regarded as his own. 



CRETAN EXPLORATION. 

 A N appeal is made by Dr. Arthur J. Evans, F.R.S., for 

 funds to complete the excavation of the " Palace of 

 Minos," which has now been carried on for seven years. 

 M the beginning of the present year it was thought that 

 supplementary explorations on a comparatively small scale 

 would be sufficient, and that by the close of the season 

 something like finality might be attained as regards at 

 least the palace site of Knossos. This forecast, however, 

 was by no means borne out by the result. The 

 season's work, which was intended to be of a more or 

 less supplementary nature, broadened out into a some- 

 what extensive excavation, the result of which is to 

 show that another great campaign must be carried 

 through before the excavation of the palace site at 

 Knossos approaches completion. It is estimated that 

 at least another 3000Z. is required to complete the work, 

 and this must be met by public subscription, for, as 

 Dr. Evans points out, in this matter it is unfortunately 

 impossible for an English explorer to rely, like his French, 

 German, and Italian colleagues, on Government grants 

 or large subventions from national academies. Writing in 

 support of the appeal in the Times of November 21, Prof. 

 C. Waldstein, referring to Cretan exploration as a scien- 



NO. 1Q90, VOL. yy] 



tlfic labour which has brought credit to the British nation 

 all over the world, says : — " In any other European 

 country the Government would have subsidised, if not 

 paid, all the expenses of what can in no way be considered 

 a private enterprise. . . . Does not a wider public take 

 some interest in the higher research carried on by the 

 scientific representatives of the nation, and can the 

 wealthier classes in England not be brought to give 

 material support to the efforts of those who thus stand 

 for the nation's higher culture? Is it impossible to hope 

 for a Government subsidy? If it be not the 'tradition,* 

 good traditions can be inaugurated by those who lead the 

 nation. No amount of immediate effort to raise our indus- 

 tries by direct technical education will prepare us to cbpe 

 with the competition of the other leading nations of the 

 world. We must raise the tone of intellectuality by 

 arousing the national interest in the highest forms of 

 intellectual life." Subscriptions for the Cretan Exploration 

 Fund can be sent either to Mr. G. A. Macmlllan, St. 

 Martin's Street, W.C., or to Messrs. Robarts, Lubbock, 

 and Co., Lombard Street. 



A LUNAR " NEW JERUSALEM." 

 A P.AMPHLET has been received containing a series of 

 ■^^ lectures by the Rev. G. B. Berry on " The New 

 Jerusalem," with a preface by the Lord Bishop of Exeter. 

 With the spiritual interpretation of the Apocalypse we 

 are not concerned in these columns, but an astonishing 

 speculation put forward in the last lecture demands a 

 word of comment. Mr. Berry suggests that the invisible 

 part of the moon has the same size and shape as the 

 mighty pyramid which, according to Revelation, forms the 

 heavenly Jerusalem. Eventually the lunar hemisphere- 

 visible to us is to bury itself in the earth, and the pyra- 

 midal portion is to project above " the rack and ruin of 

 the elements " caused by the catastrophe, and to be the 

 Celestial City in which the faithful will pass eternity. 

 As a vision, this picture may appeal to imaginative minds, 

 but from the point of view of celestial mechanics it can 

 scarcely be taken seriously. A pyramid of the dimensions 

 of that upon which Mr. Berry's New Jerusalem rises tier 

 upon tier would be crushed by its own weight even if it 

 were built of steel. As, however, the structure is 

 visionary, we imagine that this material fact affords no 

 valid objection to it. The changed moment of inertia of 

 a moon with the invisible side of a pyramidal form would 

 necessitate modification of the whole theory of the physical 

 librations of our satellite ; but perhaps Mr. Berry does 

 not appreciate the force of this difficulty. He is certainly 

 not familiar with the theory of tidal friction or with the 

 fact that Laplace, who studied the physical librations, 

 showed that one side of the moon always faces the earth 

 because that position is one of dynamical stability. A 

 fuller knowledge of celestial mechanics might have made 

 Mr. Berry hesitate before erecting such a visionary struc- 

 ture as he describes upon so slender a foundation. His 

 views would have pleased mediaeval schoolmen, but modern 

 science demands that even the most fascinating hypothesis 

 should be based upon results of observation capable of 

 being put to the test of inquiry rather than upon " revealed 

 truth " to be accepted without criticism. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



The governing body of the South-Western Polytechnic 

 has appointed Dr. Louis Lownds head of the department 

 of physics. Dr. Low-nds is the author of papers on the 

 thermoelectric and thermomagnetic properties of bismuth 

 crystals and on other subjects. Dr. W. H. Eccles, 

 formerly head of the joint mathematical and physical 

 department, has been made head of the department of 

 mathematics. 



The annual distribution of prizes and certificates at the 

 Borough Polvtechnic Institute was held on Thursday, 

 December 12,' when Sir Edward Carson, K.C., M.P., pre- 

 sented the prizes and delivered an address. Mr. Spicer, 

 the chairman of the governing body of the institute, in 

 the course of his remarks referred to the bulldina extension- 



