village of Kureika, it is about 3 miles wide, and, following the mighty stream for about another 800 miles down to the Brekoffsky Islands, it is nearly 6 miles wide. The depth of the channel varies from 50 to 100 feet above the winter level of the ice. This ice is about 3 feet thick, covered with 6 feet of snow, which becomes flooded shortly before the break up and converted into about 3 feet of ice, white as marble, which lies above the winter blue ice. When the final crash comes this field of thick ice is shatttered like glass. The irresistible force of the flood behind tears it up at an average rate of 4 miles an hour, or about a hundred miles a day, and drives it down to the sea in the form of ice floes and pack ice. Occasionally a narrow part of the channel or a sharp bend of the river causes a temporary check; but the pressure from behind is irresistible, the pack ice is piled into heaps, and the ice floes are doubled up into little mountains, which rapidly freeze together into icebergs, which float off the banks as the water rises. Meanwhile, other ice floes come up behind: some are driven into the forests, where the largest trees are mown down by them like grass, whilst others press on until the barrier gives way, and the waters, suddenly let loose, rush along at double speed, carrying the icebergs with them with irresistible force, the pent-up dam which has accumulated in the rear often covering hundreds of square miles. In very little more than a week the ice on the 800 miles from Yeniseisk to the Kureika is completely broken up, and in little more than another week the second 800 miles from the Kureika to the Brekoffsky Islands is in the same condition. During the Glacial epoch the annual fight between winter and the sun nearly always ended in the victory of the former. Even now the fight is a very desperate one within the Polar Circle, and is subject to much geographical variation. The sun alone has little or no chance. The armies of winter are clad in white armour, absolutely proof against the sun's darts, which glance harmlessly on six feet of snow. In these high latitudes the angle of incidence is very small, even at midday in midsummer. The sun's rays are reflected back into the dry air with as little effect as a shell which strikes obliquely against an armour plate. But the sun does not fight his battle alone. He has allies which, like the arrival of the Prussians on the field of Waterloo, finally determine the issue of the battle in his favour. The tide of victory turns earliest in Norway, although the Scandinavian Fjeld forms a magnificent fortress in which the forces of winter entrench themselves in vain. This fortress looks as impregnable as that on the opposite coast, and would doubtless prove so were it not for the fact that in this part of the Polar Basin the sun has a most potent ally in the Gulf Stream, which soon routs the armies of winter and compels the fortress to capitulate. The suddenness of the arrival of summer in Siberia is probably largely due to the geographical features of the country. In consequence of the vastness of the area which is drained by the great rivers, and the immense volume of water which they have to carry to the sea, the break up of the ice in their lower valleys precedes, instead of being caused by, the melting of the snow towards the limit of forest growth. The ice on the affluents either breaks up after that on the main river, or is broken up by irresistible currents from it which flow up stream; an anomaly for which the pioneer voyager is seldom prepared; and when the captain has escaped the danger of battling against an attack of pack ice and ice floes from a quarter whence it was entirely unexpected, he may be suddenly called upon to face a second army of more formidable ice floes and pack ice from the great river itself, and if his ship survive the second attack a third danger awaits him in the alternate rise and fall of the tributary as each successive barrier where the ice gets jammed in its march down the main stream below the junction of the river accumulates until the pressure from behind becomes irresistible, when it suddenly gives way. This alternate advance and retreat of the beaten armies of winter continued for about ten days during the battle between summer and winter of which I was a witness in the valley of the Yenisei. On one occasion I calculated that at least 50,000 acres of pack ice and ice floes had been marched up the Kureika. The marvel is what became of it. To all appearance half of it never came back. Some of it no doubt melted away during the ten days' marches and counter-marches, some drifted away from the river on the flooded places, which are often many square miles in extent, some got lost in the adjoining forests, and was doubtless stranded amongst the trees when the flood subsided, and some was piled up in layers one upon the top of the other, which more or less imperfectly froze together and formed icebergs of various shapes and sizes. Some of the icebergs which we saw going down the main stream were of great size, and as nearly as we could estimate stood from 20 to 30 feet above the surface of the water. These immense blocks appeared to be moving at the rate of from 10 to 20 miles an hour. The grinding together of the sharp edges of the innumerable masses of ice as they were driven down stream by the irresistible pressure from behind produced a shrill rustling sound that could be heard a mile from the river. The alternate marching of this immense quantity of ice up and down the Kureika was a most curious phenomenon. To see a strong current up stream for many hours is so contrary to all previous experience of the behaviour of rivers that one cannot help feeling continuous astonishment at the novel sight. The monotony which might otherwise have intervened in a ten-days' march-past of ice was continually broken by complete changes in the scene. Sometimes the current was up stream, sometimes it was down, and occasionally there was no current at all. Frequently the pack ice and ice floes were so closely jammed together that there was no apparent difficulty in scrambling across them, and occasionally the river was free from ice for a short time. At other times the river was thinly sprinkled over with ice blocks and little icebergs, which occasionally' calved' as they travelled on, with much commotion and splashing. The phenomenon technically called 'calving' is curious, and sometimes quite startling. It takes place when a number of scattered ice blocks are quietly floating down stream. All at once a loud splash is heard as a huge lump of ice rises out of the water, evidently from a considerable depth, like a young whale coming up to breathe, noisily beats back the waves that the sudden upheaval has caused, and rocks to and fro for some time before it finally settles down to its floating level. There can be little doubt that what looks like a comparatively small ice block floating innocently along is really the top of a formidable iceberg, the greater part of which is a submerged mass of layers of ice piled one on the top of the other, and in many places very imperfectly frozen together. By some accident, perhaps by grounding on a hidden sandbank, perhaps by the water getting between the layers and thawing the few places where they are frozen together, the bottom layer becomes detached, escapes to the surface, and loudly asserts its commencement of an independent existence with the commotion in the water which generally proclaims the fact that an iceberg has calved. Finally comes the last march-past of the beaten forces of winter, the ragtag and bobtail of the great Arctic army that comes straggling down the river when the campaign is all over-worn and weather-beaten little icebergs, dirty ice floes that look like floating sandbanks, and straggling pack ice in the last stages of consumption that looks strangely out of place under a burning sun between banks gay with the gayest flowers, amidst the buzz of mosquitoes, the music of song birds, and the harsh cries of gulls, divers, ducks, and sandpipers of various species. I have been thus diffuse in describing these scenes, in the first place, because they are very grand; in the second place, because they have so important a bearing upon climate, one of the great factors which determine the geographical distribution of animals and plants; and in the third place, because they have never been sufficiently emphasised. The following Papers were read : 1. A Journey across Australia. By GUY BOOTHBY. Leaving Thursday Island, in Torres Straits, the author and one companion sailed to Townsville. From Townsville they passed by land, through Charters Towers, the Gilberton, Etheridge, and Croydon goldfields, to Normanton, on the Norman River, Gulf of Carpentaria. Here saddle and pack-horses were obtained, stores laid in, and the transcontinental journey to Adelaide commenced. The route followed was almost due south as far as the Cloncurry mineral fields, thence due east to Hughenden, south-west to Winton, due west to Boulia, only to be driven back again by drought as far as the Thomson River. In a futile attempt to reach the South Australian border at Haddon's Corner, Windorah was reached, but at this stage scarcity of water and horse feed compelled the travellers to abandon their intention, and, after losing two horses from thirst and starvation, to retrace their steps as far as the Barcoo River. This river was eventually followed down, and the Cheviot and Grey ranges crossed to Adavale, where a course was steered along the Bulloo River, and ultimately along the Paroo. Cunnamulla, on the Warrego, was reached, and the river followed down across the Queensland border into New South Wales. Arriving in the town of Bourke, on the Darling River, the remaining horses were disposed of and a rowing boat purchased, in which a distance of 800 miles was traversed to the small town of Menindee, whence a river steamer conveyed them on to Wentworth, whence by the Murray and by train Adelaide was reached, exactly a year and a month after leaving Normanton. 2. On the Islands of Chiloë. By Mrs. LILLY GROVE, F.R.G.S. The Archipelago of Chiloë, lying between 41° and 43° S. lat., is only 25 miles distant from the mainland at its nearest point. The principal island, Chiloë, can be reached by steamer or by one of the native sailing-vessels, which are well managed by the hardy and dexterous 'Chilotes.' These vessels form the chief means of communication, as the postal service is irregular. The island is peaceful and prosperous, and crime is rare among its gentle and hospitable inhabitants. Education is improving. Agriculture and wood-cutting are the chief employments both of men and women. They have few wants; fish and the potato are their main articles of food. Wages are generally paid in kind, often, unfortunately, in alcohol. It is interesting to note that the potato (called patata or papas) is ef Chilian origin, and grows in the wildest districts, even at the top of the highest mountains. A whole region is called after it, and it is sometimes the sole food of the people. Other interesting native plants are the Latué (similar to belladonna), an infusion of which produces temporary madness; the Pangue, valuable as an astringent; the Piñon, rising to a majestic height, with a white resin, also useful medicinally; the Canelo, whose branches are recognised as a flag of truce; and the Alerce, large forests of which are found near Castro and Ancud, and whose wood is most valuable for building purposes; but better means of transport are needed in order to work these forests economically. Fishing is a very important industry, both in Chiloe and the Guaytecas. Telegraphic communication between the lastnamed islands and the mainland would be of great service, and the Government of Chile should make fishing and shooting regulations to prevent the extermination of the seals, whose skins are prepared near Dalcahue. The chief ports are Ancud and Castro, the latter of which is very picturesque. 3. On Recent Explorations in Katanga. By E. G. RAVENSTEIN. A brief account was given of the recent Belgian expeditions to the Katanga country, including the journeys of Delcommune, Captain Stairs, Bia, and Franqui. A summary of the physical geography of the region, its resources and people, was given. 4. Pictures of Japan. By Professor J. MILNE, F.R.S. This paper took the form of an explanation of an important series of lantern photographs illustrating the earthquake phenomena of Japan. 1893. 3 H FRIDAY, SEPTEMBER 15, The following Papers and Reports were read:— 1. On the Limits between Physical Geography and Geology.1 2. On the Relations of Geology to Physical Geography. By W. TOPLEY, F.R.S., Geological Survey of England. Professor Lapworth in his address to the Geological Section last year at Edinburgh showed clearly the close relationship of geology to physical geography as regards the larger features of the earth's surface-the structure and distribution of mountain chains, the great folds which traverse the earth's crust, and the wider areas of uplift and depression. I propose to refer mainly to the minor features of the surface, and to show that the nature and 'lie' of the rocks determine these surface features. From this point of view geology forms the basis of physical geography, and a geographer must necessarily be to some extent a geologist. There is no need to point out that the converse of this is equally true. A geologist who would understand in what way existing geological conditions have been brought about-how strata have been deposited, volcanic rocks erupted, and how denudation has carved the surface into its present shape-must study similar phenomena now in progress. A comparison of geological and physical maps of any area at once shows that different rock-groups and formations present different types of land, the hills and mountain chains coinciding with the outcrop of certain rocks or strata, whilst other formations are characterised by plains or by lowlands. It is thus clear that the geological structure of any district determines its physical geography. This relation is equally apparent when we compare the structure and surface features in detail. The older masses of rock frequently form mountainous land; the newer Paleozoic and the Secondary rocks occur mainly as a succession of plains and escarpments, each determined by the outcrops of certain beds. The history of valleys, plains, and gorges can only be understood by reference to their geology. We then see why rivers, after for a while running over wide open plains, suddenly break through hill ranges, cutting the escarpments at right angles, the explanation being that the streams began their work when the whole formed a comparatively even surface, the existing features being due to long-continued erosion. The escarpments, plains, and transverse river valleys of central and southern England and of eastern France form excellent examples of this structure. Here the geology is simple, a fairly continuous dip in one direction and different beds cropping out beneath each other in definite order. On the flanks of mountain chains this simple structure does not hold good; there the beds are frequently contorted, inverted, and thrust over each other, so that a superficial reading of the geology would give erroneous results as to the order of succession. But even here the present 'lie' of the beds has determined the physical geography, the disturbances of the rocks having been produced when they were deeply covered by other strata now removed by denudation. Some igneous rocks weather into conical hills resembling volcanic cones. The same thing often occurs in the weathering of loose sands, whilst sand is frequently blown into conical and crater-shaped hills. A hasty glance at the outward shape of such hills might mislead a traveller. Many conical hills in the south of Scotland are old volcanic vents, up which molten lava once came; but the volcanic cones have been long since removed by denudation, and what we now see are only the ' Published in the Scot. Geog. Mag., ix. (1893), pp. 633-638. once deeply-seated necks of the old volcanoes, the softer parts having been worn away. Caution is necessary in interpreting the apparent dip of strata as a means of determining geological structure; besides folding and inversions, already referred to, we have to guard against being deceived by cleavage, false-bedding, and the fan-shaped structure of mountain chains. A knowledge of the geological structure of certain rocks in any one area may mislead when applied to distant districts. The soft clays, the limestones, and sandstones of the Jurassic rocks of England are represented in the south and east of Europe by thick masses of limestone, forming prominent mountain ranges; whilst the soft Triassic rocks of England are represented in the Alpine area by huge masses of limestone and dolomite, with intermediate soft bands and with layers of volcanic rock. Even within so small an area as England we have differences in geological composition, making differences in physical geography. The high and barren moorlands of north-east Yorkshire and the fertile districts of the Cotteswold Hills are both composed of Lower Oolitic rocks: in the former they are sandstones and shales, in the latter they are in great part soft limestones and clays. The nature of the rock determines the character of the soils and vegetation, the soils being due to the decomposition of the underlying rocks. This is not, however, the case where the solid rocks are covered by drift deposits: here the soils are formed by the decomposition of the drifts. The sites of early settlements and villages are generally determined by geological surface conditions, water and a dry and fairly fertile soil being required. The land divisions resulting from these early settlements are in like manner dependent on the physical features, which, however, are not usually the actual boundaries of the parishes, townships, &c. But where the hills are exceptionally high the summit or the local water parting is often the boundary. [A discussion followed the reading of these papers, and is printed in full in the 'Geographical Journal' for December 1893, pp. 518–534.] 3. Report on Scottish Place Names.-See Reports, p. 554. 4. Report of the Karakoram Expedition.-See Reports, p. 564. 5. On the Influence of Land and Water on the Temperature of the Air. By J. Y. BUCHANAN, F.R.S. 6. The Temperature and Density of Sea Water between the Atlantic Ocean and North Sea. By H. N. DICKSON, F.R.S.E. At the instance of the Fishery Board for Scotland the author spent the greater part of August 1893, on H.M.S.Jackal,' in investigating the distribution of temperature and salinity on the northern and western borders of the continental shelf. Starting from a point fifty-four miles due north of the Shetlands, a line of soundings was run eastwards for about seventy miles in depths of 100 to 200 fathoms, and this was backed by a return line further south in shallower water. A line was next run from the north of the Shetlands to Suderö, Færo Islands, temperatures being observed at depths down to 416 fathoms in the Færo Shetland Channel. From Færo a line of soundings was made to latitude 59° 45′ N., longitude 5o W., whence a due easterly course was made to longitude 1o E. The latter part of the cruise was occupied with a further study of the conditions existing to the east of A full report will be published in the Annual Report of the Fishery Board for Scotland for 1894. |