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THE POPULAR SCIENCE MONTHLY. 



gineers and men of science. Lastly, the 

 more homely subject of house-building offers 

 at this moment special inducements to con- 

 structive genius." "Nature" fears, however, 

 that the prominent part in speeding prog- 

 ress 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 ar- 

 chitecture, " 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 be- 

 tween science and art is far more close and 

 cordial than with us. Every practical con- 

 structor or manufacturer is anxious to know 

 all he can of science ; every scientific pro- 

 fessor desires to mix practice with his theory. 

 Thus, on the one hand, we find ordinary en- 

 gineers drawing on all the resources of math- 

 ematics for the solution of such problems 

 as the proper section of rails or the resist- 

 ance of trains ; on the other hand, we see 

 Clausius, perhaps the greatest of German 

 physicists, devoting two long papers to in- 

 vestigate the working theory of the dynamo- 

 machine." 



Intiqnity of Fossil Hnman Skeletons. — 



Mr. T. V. Holmes, of the Essex Field Club, 

 England, discussing the recent " find " of a 

 human skeleton in the alluvial clays of Til- 

 bury, showed that the skeleton was com- 

 paratively recent, though undoubtedly pre- 

 historic, 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 geolo- 

 gists. 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 hu- 

 man 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 an- 

 tiquity 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. Simi- 

 larly, as regards the rude implements known 

 as palaeolithic, their presence could confer 

 no antiquity on recent beds. 



Gathering Edible Birds'-Ncsts. — 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 cUff 900 feet in height. The 

 Black Cave is 100 feet wide, by 250 feet 

 high at the eaves, with a roof rising to ?.60 

 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 lime- 

 stone in all damp situations, where it attains 

 the thickness of about an inch, and is dark 

 brown on the outside and white in the in- 

 side. 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 co- 

 coon. 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 ex- 

 plorer 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. 



