Anniversary Address by Lord Rayleigh. [Nov. 30, 



this conclusion may be evaded by assuming an asymmetry involving colour 

 in the process by which the variability is brought about, and he remarks 

 that although the dispersions indicated by Nordmann and Tikhoff are in the 

 same direction, the amounts calculated from the best available values of 

 the parallaxes differ in the ratio of 30 to 1. In view of this discrepancy and 

 of the extreme minuteness of the dispersion that would be indicated, the 

 probabilities seem at the moment to lie on the side of Lebedew's explana- 

 tion ; doubtless further facts will be available in the near future. 



I cannot abstain from including in the achievements of the year the 

 remarkable successes in mechanical flight attained by the brothers Wright, 

 although the interest is rather social and practical than purely scientific. 

 Eor many years, in fact ever since I became acquainted with the work 

 of Penaud and Wenham, I have leaned to the opinion that flight was 

 possible as a feat. This question is now settled, and the tendency may 

 perhaps be to jump too quickly to the conclusion that what can be done 

 as a feat will soon be possible for the purposes of daily life. But there is 

 a very large gap to be bridged over ; and the argument urged by Professor 

 Newcomb and based on the principle of dynamical similarity, that the 

 difficulties must increase with the scale of the machines, goes far to 

 preclude the idea that regular ocean service will be conducted by flying 

 machines rather than by ships. But, as the history of science and invention 

 abundantly proves, it is rash to set limits. For special purposes, such as 

 exploration, we may expect to see flying machines in use before many years 

 have passed. 



The Eeport of the National Physical Laboratory for the year again indicates 

 remarkable growth. The various new buildings, which have been erected 

 and equipped during recent years at a -cost of about £33,000, are now 

 occupied ; and the result is that both researches and test work can be carried 

 out with much greater ease and efficiency than previously. The Executive 

 Committee in charge of the Laboratory is indebted in the first instance to 

 H.M. Government, and then to the numerous friends whose assistance has 

 made this possible. At the same time, the needs for buildings are not nearly 

 satisfied. There has been during the year a very marked and important 

 growth in the demand by manufacturers and others for assistance in metal- 

 lurgical enquiries, which require investigations, frequently of a very complex 

 character ; and with the present accommodation for much of the Metallur- 

 gical Department this demand is difficult to satisfy. Thanks in great 

 measure to the Goldsmiths' Company, the chemical side of this department is 

 well provided for ; but new buildings for the other branches of metallurgy 

 &xe an urgent want. 



