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SCIENCE 



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Friday, September 23, 1921 



Address of the President of the British Asso- 

 ciation for tlw Advancement of Science: 

 Sir T. Edward Thorpe 257 



Aerial Observation of EarthquaJce Bifts: Dr. 

 Bailey Willis 266 



Scientific Events : 



International Exploration of the Upper Air; 

 The World's Supply of Wlieat; An English 

 View of American Biology; The Retirement 

 of Dr. W. E. Jordan 268 



Scientific Notes and News 271 



University and Educational News 273 



Discussion and Correspondence : 



Sauropod Dinosaur Semains in the Upper 

 Cretaceous of New Mexico : Charles W. Gil- 

 more. Leaf Stripe Disease of Sugar Cane in 

 the Philippines: Dr. H. Atherton Lee 

 and Mariano G. Medalla. English Pronun- 

 ciation for the Metric System: Professor 

 Thaddeus L. Bolton. Gregor Mendel and 

 the Support of Scientific WorTc at Briinn: 

 Professor E. B. Baboock 274 



Notes on Meteorology and Climatology : 

 Determining the True Mean Temperature: 

 C. LeRoy Meisinger 276 



Special Articles: 



On the Elimination of the X-chromosome 

 from the Egg of Drosophila melanogaster hy 

 X-raiys: Dr. James W. Mayor. Epidemic 

 Pneumonia in Beptiles: Dr. G. A. Mac- 

 Callum 277 



The Ohio Academy of Science: Professor Ed- 

 ward L. Rice 281 



MSS. intended for 'publication and books, etc., intended for 

 review should be sent to The Editor of Science, Garrison-on- 

 Hudson, N. Y. 



ADDRESS OF THE PRESIDENT OF THE 



BRITISH ASSOCIATION FOR THE 



ADVANCEMENT OF SCIENCE i 



II 



I TURN now to a question of scientific 

 interest which is attracting general attention 

 at the present time. It is directly connected 

 with Lord Kelvin's address fifty years ago. 



The. molecular theory of matter — a theory 

 which in its crudest form has descended to us 

 from the earliest times and which has been 

 elaborated by various speculative thinkers 

 through the intervening ages, hardly rested 

 upon an experimental basis until within the 

 memory of men still living. When Lord 

 Kelvin spoke in 1871, the best-established 

 development of the molecular hypothesis was 

 exhibited in the kinetic theory of gases as 

 worked out by Joule, Clausius, and Clerk-Max- 

 well. As he then said, no such comprehensive 

 molecular theory had ever been even imagined 

 before the nineteenth century. But, with the 

 eye of faith, he clearly perceived that, definite 

 and complete in its area as it was, it was " but 

 a well-drawn part of a great chart, in which all 

 physical science will be represented with every 

 property of matter shown in dynamical rela- 

 tion to the whole. The prospect we now have 

 of an early completion of this chart is based 

 on the assumption of atoms. But there can 

 be no permanent satisfaction to the mind in 

 explaining heat, light, elasticity, diilusion, 

 electricity and magnetism, in gases, liquids 

 and solids, and describing precisely the rela- 

 tions of these different states of matter to one 

 another by statistics of great numbers of atoms 

 when properties of the atom itself are simply 

 assumed. When the theory, of which we 

 have the first instalment in Clausius and Max- 

 well's work, is complete, we are but brought 

 face to face with a sui>erlatively grand ques- 



1 Edinburgh, September 7, 1921. 



