Pictures of the Rhone glacier published in the year 1820 and in the eighteenth century show that in old days the terminal ice-fall did not end abruptly in a narrowed "snout," as it does now, but spread out into a very broad half-dome or fan-shaped, apron-like expanse, some 700 feet high and a quarter of a mile broad at the base. It was considered one of the wonders of Switzerland, and was pictured in an exaggerated way in travellers' books. In 1873, when I first drove down the Furka road and saw the Rhone glacier, this wonderful, apron-like, terminal expansion of the glacier was still in existence. It has now completely disappeared. In those days, and for many years later, there was only a mule-path over the adjacent Grimsel Pass, but now there is a carriage road leading out of the Rhone glacier's basin northwards to Meiringen, whilst the old-established Furka road, at the other side of the amphitheatre, leads eastward to Andermatt, the St. Gothard, and the Lake of Lucerne. Hence three great roads now meet at Gletsch. Before leaving this wondrous spot we inspected some plump marmots, who were leading a happy life of ease and plenty in a large cage erected in front of the hotel; then in absolutely perfect weather we mounted the Grimsel road. We heard the frequent whistling of uncaged marmots as we ascended, and saw many of the little beasts sitting up on the rocks and diving into concealing crevices as we approached, just as do their smaller but closely allied cousins the prairie marmots (so-called "prairie dogs") of North America. The view, as one ascends the Grimsel, of the snow-peaks around Gletsch is a fine one in itself, but is vastly enhanced in beauty by the plunge downwards of the rocky gorge made by the Rhone as it leaves the flat-bottomed amphitheatre of its birth. The top of the Grimsel Pass, which is a little over 7,000 feet above sea-level, is the most desolate and bare of all such mountain passes. The rock is dark grey, almost black, and of unusually hard character. It is unstratified, and so resistant that it is everywhere worn into smooth, rounded surfaces, instead of being splintered and shattered. A small, black-looking lake at the top of the pass contains to this day the bones of 500 Austrians and French who fought here in 1799. It is called the Totensee, or Dead Men's Lake. At this point one stands on a great watershed, dividing the rivers of the north from the rivers of the south. You may put one foot in a rivulet which is carrying water down the Aar Valley, and through the Lakes of Brienz and of Thun to the Rhine and North Sea, whilst you keep the other in another little stream, whose particles will pass by the Rhone gorge and valley through the Lake of Geneva to the great Rhone and the Mediterranean. Three incomparably fine days—September 17th, 18th, and 19th—atoned for three weeks of sunless cloud. One of them we spent in the high valley of Rosenlaui, where are hairy-lipped gentians and the blue-iced glacier, but of these I have not space to tell. Then the clouds and the rain resumed their odious domination, and we left Lucerne and its lakes invisible, overwhelmed in grey fog, and made for Paris.
October, 1910
CHAPTER IV
THE PROBLEM OF THE GALLOPING HORSE
Until instantaneous photography was introduced, a little more than twenty-five years ago (by the discovery of the means of increasing the sensitiveness of a photographic plate), and gradually became familiar to everyone in the exhibitions known as the "biograph" or "cinematograph," the actual position of the legs in a galloping horse at any given fraction of a second was unknown. Anyone who has tried to "see" their position will agree that it cannot be done. Attempts had been made to make out what the movements and positions of the legs "must" be, by studying the hoof-marks in a soft track laid for the purpose. But the result was not satisfactory.
As everyone knows, the so-called "biograph" pictures are produced by an enormous series of consecutive instantaneous photographs taken on a continuous transparent flexible film or ribbon. The camera has a mechanism attached to it by which the sensitive film is jerked along so as to expose a length of two inches (the size of the picture given by the camera) for, say, one-thirtieth of a second without movement. The film is then jerked on and a second bit of two inches is brought into place for a thirtieth of a second and so on until a ribbon of some thousand pictures is obtained. The interval between each picture is usually also about one-thirtieth of a second, so that at least fifteen pictures are taken in every second of time, and according to the requirements of illumination and the rapidity of the movements of the men or animals photographed this number may be greatly increased. The film is developed, printed and fixed on a similar rolling mechanism and the pictures are thrown one by one by a powerful lantern on to a screen, and are jerked along at the same rate as that at which they were taken, and are magnified enormously. Animals and men in rapid movement, railway trains, the waves of the sea are thus photographed, and when the serial pictures are thrown successively on the screen the result is that the eye detects no interval between the successive pictures—the figures appear as continuous moving objects. This is due to the fact that whilst the impression produced on the retina of the eye by each picture lasts for a tenth of a second (less with brighter light), the interval between the successive pictures is only one-thirtieth of a second, and accordingly the retinal impression has not gone or ceased before the next is there; hence there is no break in the series of retinal impressions, but continuity.[1]
