May 21, 1874] 



NATURE 



53 



and the polar water to lie nearer to the surface in this 

 ocean than in the North Atlantic, that therefore this 

 proves the truth of his theory. This condition of mat- 

 ters is just as consistent with my theory as with his. 

 When we consider the immense quantity of warm surface 

 water which, as has been proved,* is being constantly 

 transferred from the South into the North Atlantic — a 

 quantity which to a large extent is compensated by cold 

 currents from the Antarctic regions — we readily under- 

 stand how the polar water comes nearer to the surface in 

 the former ocean than in the latter. In fact the whole 

 phenomena is just as easily explained upon the principle 

 of undcr-currents as upon Dr. Carpenter's theory. 



Dr. Carpenter lays considerable stress on the im- 

 portant fact established by the Cliallcnger expedition, 

 \h. that the great depths of the sea in equatorial regions 

 are occupied by ice-cold water, while the portion heated 

 by the sun's rays is simply a thin stratum at the surface. 

 It seems to me that it would be difficult to find a fact 

 more hostile to his theory than this. Were it not for this 

 upper stratum of heated water there would be no differ- 

 ence between the equatorial and polar columns, and con- 

 sequently nothing to produce motion. But the thinner 

 this stratum is the less is the difference and the less there 

 is to produce motion. I have been favoured by the Hydro- 

 grapher to the Admiralty with a series of temperature 

 soundings taken along the equator, and from these I find 

 that to so small a depth does the super-heating extend 

 that the surface of the ocean at the equator requires to 

 stand only four and a half feet above that at the poles in 

 order to the ocean being in perfect equilibrium. In this 

 case if we suppose, in order to constant circulation, that 

 the polar column is kept in excess of the equatorial by 

 the weight of say two feet of water, there would then re- 

 main only a slope of two and a half feet between the 

 equator and poles. 



There is another point to which, with some reluctance, 

 I am compelled to refer. Dr. Carpenter is continually 

 representing that eminent physicists have adopted his 

 theories while none of them share in my objections. I 

 can assure Dr. Carpenter that such is not the case. 

 Only a few weeks ago one of the most eminent mathe- 

 matical physicists of the present day stated to me that no 

 one familiar with the elements of physics and mechanics, 

 who would be at the trouble to make himself acquainted 

 with Dr. Carpenter's theories, could ever adopt them. 



James Croll 



BIOLOGY AT CAMBRIDGE 



ON the evening of Monday, i ith inst., Cambridge biolo- 

 gists mustered at least a hundred strong at the meet- 

 ing of the Philosophical Society to hear a communication 

 from Prof Huxley, one of the honorary members of the 

 Society, on the morphological conclusions to be drawn 

 from the distribution of the cranial nerves, with especial 

 reference to those of the seventh pair. Prof. C. B. 

 Babington, F.R. S., president of the Society, occupied the 

 chair. Prof. Huxley took occasion to refer in terms of 

 the highest commendation to the researches of Stannius 

 more than twenty years ago, on the morphological teaching 

 to be derived from studying the distribution of nerves, and 

 also spoke of the deductions drawn from nerve-supply by 

 Gegenbaur, especially in his work on the " Skulls of Pla- 

 giostomous Fishes." Prof. Huxley sketched in considerable 

 detail the distribution of the portio dura or seventh cranial 

 nerve in man, and compared it with the homologous 

 nerve in the frog, showmg how the arrangements of 

 branches, especially the course of the chorda tympani, 

 which seemed anomalous in man, were a necessary con- 

 sequence of perfectly obvious and natural arrangements 

 in the lower vertebrates. He also demonstrated how the 

 morphology of the parts might be learnt from such homo- 



* Phil, Mag. for March 1S74, p. 170. 



logies ; how a circuitous and apparently useless path 

 taken by a nerve was full of meaning and instruction, 

 and when studied in connection with facts of development 

 and function would lead to an explanation which might 

 be very much trusted. The relation of the tympano- 

 eustachian tube to the bifurcation of the seventh nerve was 

 dwelt upon, as leading to the identification of the com- 

 paratively small and simple auditory passage of the frog 

 with the complex one of the mammal, and further to the 

 homological identity of these passages with the spiracle of 

 the Plagiostomes. Thedistributionof the fifth and seventh 

 pairs of cranial nerves was held to agree with the view, 

 suggested by development, that the trabecular arch is a 

 pre-oral visceral arch, and that the pterygo-palatine is but 

 an outgrowth of the mandibular arch. 



The paper, which was illustrated by black-board 

 drawing, with the professor's well-known aptitude, and 

 which was a model of lucidity and careful reasoning, was 

 loudly applauded. In a discussion which followed, Prof. 

 Humphry drew attention to labours of his own having the 

 object of showing the valueof the teaching of nerve distribu- 

 tion. He acknowledged thestrongcase which wasnowmade 

 out in favour of the trabecular arch taking its position in 

 the series of visceral arches, and thought that Prof Parker's 

 paper on the development of the pig's skull made it 

 almost equally clear that the pterygo-palatine arch was 

 similar in homology. It was also remarked that the same 

 conclusions seemed deducible from Prof Parker's paper on 

 the development of the salmon, where the pterygo-palatine 

 arch was distinct from the first and in all respects like the 

 other visceral arches. 



The practical class for the study of elementary biology, 

 conducted by Dr. Michael Foster and Dr. Martin, is very 

 successful this term. When thirty students entered last 

 year the number was thought very large, and it was made 

 up of men of several years who had previously had no 

 opportunity of attending such a course. It was expected 

 that a much smaller number would attend this year ; but 

 the large number of nearly forty have availed themselves 

 of the course, and work proceeds in a most satisfactory 

 and instructive fashion. Adequate superintendence is 

 provided at all hours of the working day by the co-opera- 

 tion of four advanced students in addition to the lecturers. 

 These are Messrs. P. H. Carpenter, Trinity College, 

 A. M. Marshall, B.Sc, and Langley, St. John's College, 

 and S. H. Vines, B. Sc, Christ's College. 



G. T. Bettany 



NOTES 



On Tuesday, Sir Samuel Baker delivered the Rede lecture in 

 the Senate House, Cambridge, before a numerous assemblage, 

 which included all the leading men of the University iu resi- 

 dence, and many ladies. The subject of the address was 

 "Slavery," and Sir Samuel's narrative of his personal expe- 

 riences in Africa was listened to with much interest. 



It is said to be in contemplation to confer honorary degrees 

 at the Cambridge commencement upon Sir Bartle Frere, Sir 

 Oarnet Wolesley, Sir James Paget, and Prof. Helmholtz. 



It is stated that if the authorities of Owens College, 

 Manchester, can show that they really require it, Government 

 are prepared to make a considerable grant ot money to the 

 College ; 



The Founder's Medal of the Royal Geographical Society has 

 been granted to Dr. Schweinfurth, and the Victoria Medal to 

 Col. P. E. Warburton, who recently succeeded in crossing the 

 interior of Western Australia. 



Ev later advices from Australia we learn that Major \\'arburton 

 accomplished exactly what he set out to do. He traversed the 

 continent from tlie MacDonnell Ranges to the coast north of 



