446 



NATURE 



[February 2, 191 1 



a flight of gulls, a stork leaving its nest, and a flying 

 vulture, are particularly good. 



The author separates birds into four groups, accord- 

 ing to the characteristics of their flight, as follows : — 

 (i) Wings always flapping; (2) flapping alternating 

 with downward gliding ; (3) Flapping and gliding with 

 maintained level ; (4) gliding and soaring only. 



This classification can hardly be considered satis- 

 factory. It is suggested that a bird can fly without 

 any expenditure of work provided that there is even 

 a slightly variable wind, and the article concludes with 

 the hope that the day is not far distant when (by 

 proper automatic devices to take advantage of wind 

 variation) flying machines will be able to do without 

 engines. 



In reality no bird or flying machine can maintain 



SCIENCE AND LITERATURE. 



A N eloquent address on language and literature was 

 ■^*- delivered on January 27 by Lord Morley of 

 Blackburn, as president of the English Association. 

 Parts of the address dealt with the relation between 

 science and letters, with particular reference to the 

 use of scientific knowledge in poetry, and the anti- 

 thesis between documentary fact and artistic style. 

 Science aims at concise and truthful expression ; and 

 while Lord Morley testified to the value of its influence 

 upon literature, he doubted whether scientific ideas 

 had inspired even Tennyson to the best verse, whether 

 the desire for fact scientifically recorded is not a mis- 

 fortune in the treatment of modern history, and 

 whether concentration upon scientific truth has not a 



A group of Gulls in flight, showing various positions of the wings of birds. 



its level or rise in still air or in a uniform horizontal 

 wind without the expenditure of power, and although 

 it is true that power may be gained from the air by 

 a proper utilisation of the differences of the horizontal 

 velocity in the different regions traversed, these differ- 

 ences w-ould have to be large even for the sustenance of 

 long-winged birds, and there is no direct evidence that 

 this kind of flight is habitual with them. 



It is not improbable, however, that with their long 

 experience birds have found out its possibility, and the 

 skimming of some birds near the surface of the waves, 

 where the variations of velocity are great, may be a 

 case in point, but there can be little doubt that when 

 flying at a considerable height birds depend for their 

 support on an upward component in the velocitv of the 

 wind. A. Mallock. 



NO. 2153, VOL. 85] 



deadening effect upon emotional conceptions and plea, 

 sures. 



Lord Morley's tribute to some scientific masters of 

 clear and simple exposition resigns us to his subse-| 

 quent conclusions. Keats could not forgive optics forj 

 robbing the rainbow of its wonder and mystery, and] 

 Lord Morley seems to suggest, that the literary art] 

 which deals with scientific studies and results is not of | 

 the highest. But poetry is imagery, and new images 

 of Nature, are made possible by every discovery of the' 

 attributes and meaning of the things around us. The 

 poetry which neglects advances of natural knowledge 

 becomes conventional in form and substance, concern- 

 ing itself only with the wonders of childhood because 

 it does not understand the higher and grander 

 mysteries which science has failed to penetrate. His- 



