November 24, 192 1] 



NATURE 



415 



daylight," new neon electric lamps used for letter- 

 signs, etc. The last-named exhibit was of consider- 

 able scientific interest in view of the novel principle 

 of using neon gas as a luminous medium instead of a 

 ti lament within a lamp-bulb of the ordinary standard 

 size, .\nother striking demonstration illustrated the 

 application of ultra-violet rays for the purpose of 

 distinguishing genuine precious stones from spurious 

 ones. Most gems fluoresce under strong ultra-violet 

 light. Not only is the effect different in a genuine 

 gem from that met with in imitations, but it is even 

 possible to discriminate, by means of the difference in 

 the colour of the fluorescence, between gems of the 

 same kind from different districts. It was shown 

 that Indian pearls can be readily distinguished from 

 Japanese pearls by the aid of ultra-violet light, 

 although by ordinary light they can be detected only 

 with great difficulty. Ultra-violet light does not, how- 

 ever, enable "cultured" to be distinguished from 

 ordinan*' Japanese pearls. 



"Scientific Men as Citizens" was the subject of 

 an address by Sir Richard Gregory to an open meeting 

 of the Cambridge branch of the National Union of 

 Scientific Workers on November i6. In the address 

 the theme was developed that modern civilisation 

 differs from civilisations of the past, especially in 

 wealth and power, almost entirely as the result of 

 science and its application to human affairs. How 

 comes it that the scientific man, as such, does not 

 occupy a position in the community in any way com- 

 mensurate with what he has done for modern civilisa- 

 tion? The reason appears to lie in the failure of 

 scientific men as a body to grasp their own significance 

 in the social complex, their failure to take any interest 

 in the relation of their work and its application to 

 the life of the community, their failure to impress 

 their own importance and the importance of their 

 work upon the imagination of the public, upon Govern- 

 ments, and upon leaders in industn,-. Broadly speak- 

 ing, modern wealth and industrial expansion are 

 directly due to scientific men, but men of science as 

 such have taken little part in trying as citizens to 

 control the proper uses of the riches with which they 

 have helped to endow the nation. Scientific men 

 should now exert direct influence in the State, 

 and the motto of any organisation or union they 

 may form should be, "The interests of science 

 are the interests of the community, and the in- 

 terests of the community are the interests of science." 

 Sir Ernest Rutherford, who followed Sir Richard 

 Gregor\-, said that the difficulty was that scientific 

 men, both by temperament and training, were 

 unfitted for the so-called political world. The 

 remedy was for scientific men to be represented by 

 men educated and trained in science, but who also 

 possessed ability for public affairs or journalism. Prof. 

 A. C. Seward emphasised the need for, and the value 

 of, increased scientific education in schools. Prof. 

 J. Stanley Gardiner, president of the Cambridge branch 

 of the union, occupied the chair at the meeting. 



A VERY remarkable kinematograph film, illustrating 

 the method by which the cuckoo disposes of its eggs, 

 NO. 2717, VOL. 108] 



and the subsequent behaviour of the young, was ex- 

 hibited at the scientific meeting of the Zoological 

 Society on November 8. For some years these matters 

 have formed the subject of ven.- patient and methodi- 

 cal study by Mr. Edgar Chance, and this summer he 

 contrived, after an elaborately worked out plan, to 

 summarise his results with the aid of a kinemato- 

 grapher carefullv concealed within a shelter of leaves 

 and bracken. Hitherto it has been the accepted be- 

 lief that the cuckoo deposited her egg upon the ground 

 and then conveved it to the nest of her dupe in her 

 beak. This film showed clearly enough that, as a 

 matter of fact, ?he bird lays the egg within the nest, 

 which, at any rate in the case of meadow-pipits' nests, 

 she leaves tail foremost, apparently to avoid displacing 

 the "run " made by the owners of the nest. As she 

 leaves she takes in her beak one of the eggs of the 

 pipit, and presently eats it. The "planing " down 

 of the cuckoo from a high tree, and the alighting 

 within a few feet of the nest, were most realistically 

 shown. But the most wonderful of the whole series 

 of pictures were those which showed the young 

 cuckoo, though but two days old, blind, and naked, 

 making the most determined efforts to raise its foster- 

 brothers on to its back and up over the edge of the 

 nest, thrusting its lean limbs backwards to assure 

 itself by the sense of touch whether its efforts had 

 succeeded. There was something indescribably dia- 

 bolical and horrible about the whole of the proceed- 

 ings. The first attempt failed, the downy, struggling 

 body of the nestling to be ejected being saved from 

 falling over the edge of the nest by a projecting twig. 

 At this juncture the foster-mother returned and, uncon- 

 cernedly feeding both her own youngster, gasping on 

 the rim of the nest, and the young cuckoo, took both 

 and brooded them. No sooner had she left them for 

 more food than the work of eviction began afresh, and 

 this time was accomplished successfully. Immediately 

 after the only remaining rival was also thrown out. 



kT a meeting of the Royal Statistical Society on 

 November 15, Sir R. Henry Rew delivered his second 

 presidential address, taking as his subject "The Pro- 

 gress of Agriculture." He pointed out that the total 

 land area of Great Britain is now 565 million acres, 

 and of the 525 million acres capable of productive use 

 about 90 f>er cent, is so utilised in a greater or less 

 degree. This area is not capable of any material 

 extension. The proportion of arable land was 58 per 

 cent, in 1869-78, and is now 48 per cent., but the 

 prevalent belief that the output of British agriculture 

 has declined overlooks the fact that the smaller arable 

 area may, if devoted to other crops, produce a greater 

 amount of food than the larger. By substituting 

 potatoes for wheat, for instance, one-fifth the area 

 would give about as much food. Fruit and vegetables 

 have also largely replaced farm crops, while the exten- 

 sion of cultivation under glass has resulted in a great 

 increase of output per acre. As regards livestock, com- 

 paring the ten years 1869-78 with 1912-21, there has 

 been a net gain of about 750,000 beasts. There has 

 also been a progressive and substantial increase in milk 

 production during the past fifty years, the milking 



