March 3, 1898] 



NATURE 



423 



The Antarctic Ice-sheet : Duke of Argyll. 



Scientific men generally feel, I think, that they do not need to 

 give detailed reasons in connection with particular subjects of 

 inquiry, to justify their unanimous desire for an Antarctic Expe- 

 dition. It is enough, surely, for them to point out the fact that 

 a very large area of the surface of our small planet is still almost 

 unknown to us. That it should be so seems almost a reproach 

 to our civilisation. As to detailed reasons, it may almost be said 

 with truth that there is hardly one of the physical sciences on 

 which important light may not be cast by Antarctic exploration. 

 Oceanic circulation ; meteorology ; magnetism ; distribution of 

 animal and vegetable life, not only in the present but in the past ; 

 geology ; itiineralogy ; volcanic action under special conditions 

 — all of these are subjects on which the phenomena of the 

 Antarctic regions are sure to bear directly. 



If, however, I am asked to specify more particularly the 

 question on which I look for invaluable evidence which can be 

 got nowhere else, I must name, above all others, the most 

 difficult questions involved in quaternary geology. Geologists 

 are nearly all agreed that there has been, very recently, a glacial 

 age — an age in which glacial conditions prevailed over the whole 

 northern hemisphere to a much lower latitude than they prevail 

 now. But geologists differ widely and fundamentally from each 

 other as to the form which glacial agencies took during that 

 period. In particular, many geologists believe in what iheycall 

 an "ice sheet" — that is to say, in the northern world having 

 been covered by an enormous mass of ice several thousand feet 

 thick, which, as they assert, " flowed " over mountain areas as 

 well as over plains, and filled up the bed of seas of a consider- 

 able depth. Other geologists disbelieve in this agency alto- 

 gether. They deny that even such a body of ice ever existed ; 

 it could not possibly have moved in the way which the theory 

 iissunies. They affirm, also, that the facts connected with 

 glaciated surfaces do not indicate the planing down by one 

 universal sheet of enormous weight and pressure ; but, on the 

 contrary, the action of small and lighter bodies of ice, which 

 have acted partially and unequally on different surfaces differently 

 exposed. 



, We might have hoped that this controversy could be settled 

 by the facts connected with the only enormous ice-sheet which 

 exists in the northern hemisphere, viz. that which covers the 

 great continent of Greenland. But that ice-sheet, enormous 

 though it be, does certainly not do what the ice-sheet of the 

 Glacial Age is supposed to have done. That is to say, it does 

 not flow out from Greenland, fill the adjacent seas, or override 

 the opposite coasts, even in so narrow a sheet as Smith's Sound. 

 But this evidence is negative only. In the Antarctic continent 

 we have reason to believe that there is a larger ice-sheet, and it 

 certainly does protrude into the adjacent seas, not merely by 

 sending out broken, floating fragments, but in unbroken ice cliffs 

 of great height. Now we want to know exactly under what 

 conditions this protrusion takes place. Dr. Murray speaks of it 

 as "creeping" seawards — a more cautious word than " flow- 

 ing." But is it certain that it does even creep? May it not 

 simply grow by accretion or aggregation till it reaches a depth 

 of water so great as to break it off by flotation? Does it, or 

 does it not, carry detritus when no detritus has been dropped on 

 its surface ? Or does it pick up detritus from its own bed ? Or 

 does it push foreign matter before it ? Does the perfectly tabular 

 form of the Antarctic icebergs indicate any differential move- 

 ment in the parent mass at all ; or does it not indicate a con- 

 dition of immobility until their buoyancy lifts great fragments 

 off ? What is the condition of the rocks on which they rest ? Is 

 there any thrust upon the mass from the mountain ranges on 

 which the gathering ground lies ? Or is the whole country one 

 vast gathering ground from the continual excess of precipitation 

 over melting ?■ These questions, and a hundred others, have to 

 be solved by Antarctic discovery ; and until they are solved we 

 cannot argue with security on the geological history of out own 

 now temperate regions. The Antarctic continent is unquestion- 

 ably the region of the earth in which glacial conditions are at 

 their maximum, and therefore it is the region in which we must 

 look for all the information attainable towards, perhaps, the most 

 difficult problem with which geological science has to deal. 



Sir Joseph Hooker's Views. 



Dr. Murray's admirable summary of the scientific information 



obtainable by an organised exploration of the Antarctic regions, 



leaves nothing further to be said under that head. I can only 



record the satisfaction with which I heard it, and my earnest 



NO. 1479. VOL. 57] 



hope that it will lead to action being taken by the Government 

 in the, direction indicated. 



Next to a consideration of the number and complexity of the 

 objects to be obtained by an AnUrctic Expedition, what dwells 

 most in. my .imagination, is the yast area of the unknown region 

 which is to be the field for investigation — a region which, in 

 its full extension, reaches frpm the latitude of 6j° S. to the 

 Southern Pole, and embraces every degree of longitude. This 

 is a very considerable portion of the surface of the globe, and 

 it is one that has been considered to be for the most part 

 inaccessible to man ; I will, therefore, ask you to accompany the 

 scientific explorer no further than to the threshold of the 

 scenes of his labours, that you may see how soon and how 

 urgently he is called upon to study some of those hitherto 

 unsolved Antarctic problems that he will there encounter. 



In latitude 60° S. an open ocean girdles the globe without 

 break of continuity. Proceeding southwards in it, probably 

 before reaching the Antarctic Circle, he encounters the floating 

 ice fields which form a circumpolar girdle known as " The 

 Pack " approximately concentric with the oceanic, interrupted 

 in one meridian only, that south of Cape Horn, by the northern 

 prolongation of Graham's Land. Pursuing his southward 

 course in search of seas or lands beyond, after the novelty of his 

 position in the Pack has worn off, he asks where and how the 

 component parts of these great fields of ice had their origin, 

 how they arrived at, and maintain their present position, what 

 are their rate of progress and courses, and what their influence 

 on the surrounding atmosphere and ocean. I believe I am 

 right in thinking that to none of these questions can a fuller 

 answer be given, than that they originated over extensive areas 

 of open water in a higher latitude than they now occupy, that 

 they are formed of frozen ocean water and snow, and that winds 

 and currents have brought them to where we now find them. 

 But of the position of the southern, open waters, with the 

 exception of the comparatively diminutive sea east of Victoria 

 Land,^ we know nothing, nor do we know anything of the 

 relative amount of snow and ice of which they are composed, 

 or of their age, or of the winds and currents that have carried 

 them to a lower latitude. 



The other great glacial feature of the Antarctic area is " The 

 Barrier," which Ross traced for 300 miles in the 78th and 79th 

 degree of south latitude, maintaining throughout its character of 

 an inaccessible precipitous ice-cliff (the sea-front of a gigantic 

 glacier) of 150 to 200 feet in height. This stupendous glacier 

 is no doubt one parent of the huge table-topped ice-islands ' that 

 infest the higher latitudes of the Southern Ocean ; but as in the 

 case of the Pack, we do not know where the Barrier has its 

 origin, or anything further about- it than that it in great part 

 rests upon a comparatively shallow ocean bottom. It probably 

 abuts upon land, possibly on an Antarctic continent ; but to 

 prove this was impossible, on the occasion of Ross's visit, for 

 the height of the ship's crow's-nest above the sea-surface was not 

 sufficient to enable him to overlook even the upper surface of the 

 ice. Nor do I foresee any other method of settling this 

 important point, except by the use of a captive balloon, an 

 implement with which I hope that future expeditions may be 

 supplied. There were several occasions in which such an 

 implement might advantageously have been used by Ross when 

 near the Barrier, and more when it would have greatly 

 facilitated his navigation of the Pack 



I have chosen the Antarctic Ice as the subject upon which to 

 address this most important meeting, not only because it is 

 one of the very first of the phenomena that demand the study of 

 the explorer, but because it is the dominant feature in Antarctic 

 navigation, where the Pack is ever present or close by, demand- 

 ing, whether for being penetrated or evaded, all the commander's 

 fortitude and skill, and all his crew's endurance. 



It may be expected that I should allude to those sections 

 of Dr. Murray's summary that refer to the .\ntarctic fauna and 

 flora ; they are most important, for the South Polar Ocean swarms 

 with animal and vegetable life. Large collections of these, taken 

 both by the tow-net and by deep sea soundmgs, were made by 

 Sir J. Ross, who was an ardent naturalist and threw away no 

 opportunity of observing and preserving ; but unfortunately, with 

 the exception of the Diatomacese (which were investigated by 



1 I refer to the "pancake" ice, which, in that sea, on several occasions 

 formed with great rapidity around Ross's ships, in lat. 76° to 78° S. in February' 

 1842, and which arrested their progress. Such ice, augmented by further 

 freezing of the water and by snowfalls, may be regarded as a genesis of 

 fields that, when broken up by gales, are earned to the north and contribute 

 to the circumpolar Pack. 



