Page:Popular Science Monthly Volume 26.djvu/444

430 and men of science. Lastly, the more homely subject of house-building offers at this moment special inducements to constructive genius." "Nature" fears, however, that the prominent part in speeding progress in this line of invention is destined to fall to other countries than England. The latest and most important movements in the direction of cheapened transportation and the storage and transmission of power have been made in France, Germany, and America, while, in respect to scientific architecture, "England stands far nearer the bottom than the top in the scale of civilized nations." This is because "in America, in France, above all in Germany, the union between science and art is far more close and cordial than with us. Every practical constructor or manufacturer is anxious to know all he can of science; every scientific professor desires to mix practice with his theory. Thus, on the one hand, we find ordinary engineers drawing on all the resources of mathematics for the solution of such problems as the proper section of rails or the resistance of trains; on the other hand, we see Clausius, perhaps the greatest of German physicists, devoting two long papers to investigate the working theory of the dynamo machine."

Antiquity of Fossil Human Skeletons.—Mr. T. V. Holmes, of the Essex Field Club, England, discussing the recent "find" of a human skeleton in the alluvial clays of Tilbury, showed that the skeleton was comparatively recent, though undoubtedly prehistoric, and added that geological position furnishes the only absolute test of relative age. The test of association with extinct mammalia is largely dependent on negative evidence. A hint on this point was given by the results of the drainage of Haarlem Lake thirty years ago. Excellent sections were made in all directions across its bed, and carefully examined by skilled geologists. Hundreds of men were known to have perished in its waters three centuries before, and it had always been the center of a considerable population. Yet no human bones were found, though works of art were discovered. Thus hundreds, or even thousands of mammalia, incapable of producing works of art, might be interred in particular strata, and yet leave no signs whatever of their former existence two or three centuries afterward. And, on the other hand, were extinct mammalia present in the Tilbury Dock beds, no additional antiquity would thereby be conferred on the beds themselves, but the period at which the animals became extinct would be shown to be later than had been supposed. Similarly, as regards the rude implements known as palæolithic, their presence could confer no antiquity on recent beds.

Gathering Edible Birds'-Nests.—The material from which the famous Chinese bird's-nest soup is made can be obtained in quantities at only one place in the world, and this spot has been visited recently by Mr. Pryer, a naturalist of Yokohama, Japan. It is at Gomanton, some thirty miles up the Sapugaya River, in British North Borneo, in two caves, called by the natives the Black and the White Caves, which are situated in a limestone cliff 900 feet in height. The Black Cave is 100 feet wide, by 250 feet high at the eaves, with a roof rising to 360 feet high in the middle. The interior is well lighted by holes in the roof, and is filled with clusters of the nests of bats and swifts. The White Cave is 400 feet higher up. Mr. Pryer discovered the material from which the nests are made in the shape of a soft, fungoid growth that incrusts the limestone in all damp situations, where it attains the thickness of about an inch, and is dark brown on the outside and white in the inside. The birds make the black nests from the outside layer, and the white nests, which are best esteemed, from the inside. The "moss" is taken by the bird in its mouth and drawn out in a filament backward and forward, like a caterpillar weaving its cocoon. A wonderful sight is witnessed at night, when the bats fly out of the caves in a score of flocks of many thousands each, with a rushing noise, and the birds come in in a similar style, and in the morning when the birds go out and the bats come in. Near the center of the largest cave, the explorer was shown a small beam of light from a funnel at the top of the rock, exactly 696 feet above his head. The nests are gathered from these enormous elevations by means of pendent, flexible rattan ladders and stages.