SCIENCE-GOSSIP. 



3°5 



The golden oriole's nest consists of material 

 borrowed from man. Poucust, with true French 

 facetiousness, asks how the oriole made its nest 

 before man's industry supplied the material it 

 now uses. To this one may reply, the oriole 

 does not think of a particular kind of stuff, 

 whether it be wool, silk or cotton ; what it 

 requires is a fibrous material, a long body, suitably 

 flexible and strong enough for its purpose. This 

 it takes whenever and wherever it finds it. These 

 existed and built their nests long before the advent 

 of industrial man, but they always had natural 

 material convenient. In the nest of the modern 

 oriole we fail to see any modification. Nests of 

 the same species in different countries are con- 

 structed of the vegetable substances peculiar to 

 the country. 



What motive leads the tailor bird to sew leaves 

 together to make a nest ? Why does it alone 

 possess that remarkable power or have more fore- 

 sight than others ? I cannot allow the opinion of 

 Milne-Edwards, who thinks instinct is seen in the 

 general fact only and intelligence in the details. 



Still less do I agree with Dr. Alfred Wallace, 

 that they have a sort of bird-intelligence, a limited 

 rational power. Dr. Wallace conceives that birds 

 undergo a sort of discipline at the hands of the 

 more experienced, that they make use of tradition 

 and so learn to build their nests. I entirely re- 

 pudiate the notion. Observation leads to a 

 contrary opinion. The canary imprisoned in its 

 cage makes a simulacrum of a nest, although it 

 is supplied with one. Beavers removed from the 

 mother as sucklings, before they are able to 

 receive instruction, build huts and store food, 

 although in circumstances widely different from 

 the native condition. Would a child isolated from 

 its parents and removed beyond the pale of civi- 

 lized influences construct a house, as the beaver 

 its hut ? No. The child in these conditions 

 would revert to the savage state of its primitive 

 ancestors. Civilized man is merely an educated 

 savage with an indefinite capacity for self-improve- 

 ment. The truth of these statements has been 

 demonstrated on several occasions. 



I repeat the question — why does each species 

 construct its nest after a unique type ? Or, why do 

 various species not imitate one another, and that 

 when they are brought into like conditions, since 

 they employ nearly similar materials and have the 

 same instruments of construction ? These are 

 some of the insoluble riddles of natural history. 



If there is an animal at all apparently little 

 provided with the organs necessary for the con- 

 struction of a nest it is a fish. Still, in spite of 

 its apparent impotence, the stickle-back discovers 

 a remarkable ability in that direction. Having 

 selected a suitable place the male stickleback bores 

 itself head-first into the mud till it disappears. It 



then turns rapidly upon itself and makes a cylinder- 

 shaped cavity. This done, it sets out in quest of 

 blades of grass and other vegetable substances, 

 which it seizes with its mouth, and carries to its 

 dwelling. There it arranges these, secures them 

 by fixing them to the mud with its body. It 

 continues this work until the whole surface is 

 covered, then it completes it by living there and 

 lubricating them with a thick, sticky liquid secreted 

 from its sides. The nest is now finished, but I 

 need not follow it further, that is not my object. 



No stickleback, as far as we know, has been 

 found that proceeds differently from the others ; 

 and although other fishes witness the labours of 

 the stickleback, no other has been known to 

 imitate them. 



The water spider's nest is another of Nature's 

 anomalies. This animal is small, brownish in 

 colour and somewhat velvety in texture. It lives 

 in the water or at the surface of the water among 

 the leaves of aquatic plants. It is an air-breathing 

 creature, and always requires fresh air. If its nest 

 is in the water it displays a marvellous ingenuity 

 in laying up a store of the precious element. How 

 does it do this ? It turns on its back and floats 

 face upwards, collecting a quantity of air on the 

 surface of its body, it then dives, and collecting the 

 minute bubbles, makes a single one, which it fixes 

 to some support. It again rises to the surface and 

 repeats the operation until the bubble is of 

 sufficient magnitude. It then spins a web over its 

 surface, the whole being somewhat like a dress- 

 maker's thimble in shape. Small cables connected 

 with the bell and the fixture keep it suspended in 

 the water. The spider then takes up position in 

 its dwelling, when it awaits any insects that chance 

 may lead within its walls. If the bell should by any 

 means be fractured, the spider repairs the part ; 

 if the air be vitiated, it is removed by making the 

 bell perform a somersault in the water, and so 

 emptying its contents, it then refills it as before. 

 These interesting creatures were first observed by 

 Lignae in 1744, and since by many other observers. 

 The water spiders so far have not yet changed their 

 habits. Their performances are stamped with the 

 immutable characteristics of instinct. 

 (To be continued.) 



Flicker Photometry. — This method of com- 

 paring the intensities of two sources of light, due 

 to Mr. O. N. Rood, consists in illuminating the two 

 sides of a white upright right-angled prism with 

 the two lights and rapidly rotating a cylindrical 

 lens placed opposite the angle of the prism. The 

 lens is oscillated horizontally by a toothed-wheel 

 arrangement. By this means the two illuminated 

 sides of the prism are presented rapidly in 

 succession to an eye placed behind an aperture in 

 front of the lens. Accurate results are obtained 

 by this method even by persons not versed in 

 photometric work. — James Quick, Suffolk House, 

 Dartmouth Park Hill, London, N. IV. 



