448 



NATURE 



\_Sept 8, J 88 1 



arctic plants found on the south temperate Alps, or the south 

 temperate plants found in the mountains of the tropics, originated 

 in the south ; though this appears probable from the absence in 

 the south of so many of the leading families of plants and 

 animals of the north, no less than from the number of endemic 

 forms the south contains. These considerations have favoured 

 the speculation of the former existence, during a warmer period 

 than the present, of a centre of creation in the Southern Ocean, 

 in the form of either a continent or of an archipelago, from 

 which both the Antarctic and southern endemic forms radiated. 

 I have myself suggested continental or insular extension ' as a 

 means of aiding that wide dispersion of species over the Southern 

 Ocean, which it is difficult to explain without such intervention ; 

 and the discovery of beds of fossil trunks of ti-ees in Kerguelen's 

 Island, testifies to that place having enjoyed a warmer climate 

 than its present one. 



The rarity in the existing Archipelago (Kerguelen's Island, the 

 Crozets, and Prince Edward's Island) of any of the endemic 

 genera of the south temperate flora, or of representatives of 

 them, is, however, an argument against such land, if it ever 

 existed, having been the birthplace of that flora ; and there are 

 two reasons for adopting the opposite theory, that the southern 

 flora came from the north temperate zone. Of these, one is the 

 number of northern genera and species (which, from their all 

 inhabiting north-east Europe, I have denominated Scandinavian) " 

 that are found in all Antarctic and south temperate regions, the 

 majority of them in Fuegia, the flora of which country is, by 

 means of the Andes, in the most direct communication with the 

 northern one. The other is the fact I have stated above, that 

 the several south temperate floras are more intimately related to 

 those of the countries north of them than they are to one 

 another. 



And this brings me to the latest propounded theoretical appli- 

 cation of the laws of geographical distribution. It is that 

 recently advanced by Mr. Thiselton Dyer, in a lecture "On 

 Plant Distribution as a Field of Geographical Research " ^ ; 

 wherein he argues that the floras of all the countries of the 

 globe may be traced back at some time of their history to the 

 northern hemisphere, and that they may be regarded in point of 

 affinity and specialisation as the natural results of the conditions 

 to which they must have been subjected during recent geological 

 times, on continents and islands with the configuration of those 

 of our globe. This hypothesis derives its principal support from 

 the fact that many of the most peculiar endemic plants of tlie 

 south have representatives in the north, some of them living and 

 all of them in a fossil state, whilst the northern endemic forms 

 have not hitherto been found fossil in the southern regions. So 

 that, given time, evolution, continental continuity, changes of 

 climate and elevations of the land, and all the southern types 

 may be traced back to one region of the globe, and that one 

 palaeontology teaches us is the northern. 



A very similar view has been held and published at the same 

 time by Count Saporta,'' a most eminent palajontologist, in a 

 suggestive essay entitled " L'Ancienne Vegetation Polaire." 

 Starting from Buffon's thesis, that the cooling of the globe 

 having been a gradual process, and the Polar regions having 

 cooled first, these must have first become fit for organic life. 

 Count Saporta proceeds to assume that the termination of tlie 

 azoic period coincided with a cooling of the waters to the point 

 at which coagulation of allnnuen does not take place, when 

 organic life appeared in the water itself. I have discussed 

 Count Saporta's speculations elsewhere^ ; it is sufficient here to 

 indicate the more important ones as bearing upon distribution. 

 These are that the Polar area was the centre of origination of .ill 

 the successive phases of vegetation that have ajjpeared on tlic 

 globe, all being developed in the north ; and that the develop- 

 ment of flowering plants was enormously augmented by the 

 introduction during the latter part of the secondary period of 

 flower-feeding insects, which brought about cross-fertilisation. 



It remains to allude briefly to the most important general 



made either by the__C/;a//«(^f>- expedition or by the various "transit of 

 V.^i?,"'' '''^' ^^^^ recently visited this interesting island. 



lloraAntarctica,"pp. =30,240. Seealso MoseleyinyoKra. Linn. Soc. 

 Botany, vol, xv, p. 485, and " Observations on the Botany of Kerguelen's 

 Island, by myself, in the Philosophical Transactions, vol. 168, p. 15. 



bee 'Outhnesof the Distribution of Arctic Plants," TrawMcteM of the 

 1-innean Society, vol. xxiu. p. 257. Read June, i860. 

 3 Proceedings of the Royal Geographical Society, vol. xxii. p. 415 (1E7S) 

 'Cotnptes rendus of the International Congress of Geographical Science, 

 * = A j"?^' '" ?"'^ '" '^75. but apparently not published till 1877. 



5 Address of the President delivered at the anniversary meeting of the 

 Koyal bociety of London, November 30, 1878. 



works on distribution that have appeared since the foundation of 

 this Association. Of these, the two which take the first rank 

 are Prof. Alphonse de Candolle's "Geographic Botanique" 

 and Mr. Wallace's "Geographical Distribution of Animals." 

 Prof, de Candolle's work ^ appeared at a 'critical period, when 

 the doctrine of evolution with natural selection had only just 

 been announced, and before the great influence of geological and 

 climatal changes on the dispersion of living species had been 

 fully appreciated ; nevertheless it is a great and truly philoso- 

 phical work, replete with important facts, discussed with full 

 knowledge, judgment, and scrupulous caution. Of its numer- 

 ous valuable and novel features, two clami particular notice, 

 namely, the chapters on the history of cultivated and introduced 

 plants ; and the further development of Humboldt's " Ariihme- 

 tic:e Botanices," by taking into account the sums of temperatures 

 as well as the inaxima, minima, and means, in determining the 

 amount of heat required to satisfy all the conditions of a plant's 

 life, at the various periods of its existence, and especially the 

 maturation of its seeds. 



Of Mr. Wallace's great work, "The Geographical Distribu- 

 tion of Animals," I cannot speak with sufficient knowledge of 

 the subject, and can only appreciate and echo the high praises 

 accorded to it by zoologists for its scientific treatment of a vast 

 subject. 



The "Geographie Botanique" was followed by the late Dr. 

 Grisebach's " Die Vegetation derErde,"^ which contains an ad- 

 mirable summary of the vegetation of the diflTerent regions of 

 the glol-e as limited by their physical features, divested of all 

 theoretical considerations. 



For the largest treatment in outline of the whole subject of 

 distribution, I must refer to the chapters of Darwin's "Origin of 

 Species " which are devoted to it. 



In reference to these and other works, very able and instruc- 

 tive discussions of the principles of geographical distribution are 

 to be found in the presidential addresses delivered before the 

 Linnean Society, in 1869, 1870, and 1872, by the veteran 

 botanist, G. Bentham. 



With Mr. Wallace's "Island Life" I must conclude this 

 notice, aird very fittingly, for besides presenting an admirable 

 account of the origin and migrations of aniinals and vegetables in 

 oceanic and continental islands, it contains a complete and com- 

 prehensive analysis of those past and present conditions of the 

 globe, astronomical, geological, geographical, and biological, 

 which have been the earlier and later directors and controllers 

 of the ever-warring forces of organic nature. In this work Mr. 

 Wallace independently advocates the view of the northern origin 

 of both the faunas and floras of the world. 



I conclude with the hope that I have made the subject of the 

 distribution of organic life on the globe interesting to you as 

 geographers, liy showing on the one hand how much it owes its 

 advance to the observations made and materials collected by 

 geographical explorers, and on the other how greatly the student 

 of distribution has, by the use he has made of these observations 

 and materials, advanced the science of physical geography. 



SECTION G 



MECHANICAL SCIENCE 



Opening Address by Sir W. Armstrong, C.B., D.C.L., 

 LL.D., F.R.S., President of the Section 



The astonishing progress whicli has been made in the con- 

 struction and application of machinery during the half century 

 which has elapsed since tlie nativity of the British Association 

 for the Avancement of .Science, is a theme which I miglit with 

 much complacency adopt in this address, but instead of review- 

 ing the past and exulting in our successes, it will be more profit- 

 able to look to the future and to dwell on our failures. It is 

 but justice to say that by growing experience, by increasing 

 facilities of manufacture, and by the exercise of much skill and 

 ingenuity, we have succeeded in multiplying and expanding the 

 applications of our chief motfir, the steam-engine, to an extent 

 that would have appeared incredible fifty years ago ; but the 



^ Prof. Alph. de Candolle divides his subject into bctanical geography 

 and geographical botany ; the distinction is olivious and sound, but the two 

 expressions have been so long used and regarded as synonymous, and as 

 embracing both branches, that they cannot now be limited each 10 one. 

 Perhaps the terms topographical botany and geographical be tany would prove 

 more acceptable designat'ons. 



= Published in 1872. Translated into French under the title of ' ' La Ve'ge'- 

 tation du Globe," by P. de Tchihachef, Paris, 1875. 



