ON THE VOLCANIC PHENOMENA OF JAPAN. 431 



The Imperial University has endowed a chair of seismology, which 

 is lield by Mr. K. Sekiya, an iudefatigable worker at earthquake phenomena, 

 and has established a well-equipped earthquake observatory. The Imperial 

 Meteorological Department has also established an observatory, at which, 

 in addition to the ordinary work of observing, they make and test instru- 

 ments to be used in the country. 



In these and other ways is Japan working at a study which for many 

 years has made but little progress. 



One valuable work towards which the Government of this country is 

 at present directing its attention is, how and where to construct buildings 

 which either partially or wholly may escape the effects of earthquake 

 movement. 



With these few general remarks on what is being accomplished in 

 Japan, the members of the British Association will recognise that their 

 endeavour to give an impetus to scientific investigation in the far East 

 Las not been unsuccessful. 



The Modern Development of Thomas Yoiincfs Theory of 

 Colour-vision. By Dr. Arthur Konig. 



[A commumcation ordered by the General Committee to be printed in externa 



among the Eeports.] 



§ 1. In the third book of his ' Optics ' Isaac Newton puts the question, 

 whether the sensation of colour is brought about by some sort of vibrations 

 which the light produces in the constituents of the retina. 



In a paper read before the Royal Society of London in 1801 Thomas 

 Young makes an observation bearing upon this statement of Newton, in 

 which he points out that the number of those vibrations depends on the 

 nature of the above-mentioned constituents. 



The infinite number of perceptible colours requires an infinite number 

 of various constituents in each surface element of the retina. This is an 

 impossible supposition. But we can explain all phenomena of colour-per- 

 ception by supposing that each surface element of the retina consists of 

 three constituents, each of which, when affected, causes a different colour- 

 sensation. On this supposition all the various shades of colour are resultants 

 of three fundamental sensations originating in those constituents. Later on 

 Thomas Young proposes red, green, and violet as these fundamental sen- 

 sations. It is true that he does not explicitly say that the sensation of 

 white is the resultant of the simultaneous action of all the three consti- 

 tuents, but this is a self-evident conclusion if his supposition is to explain 

 the famous experiment of Newton. 



The principle which he intuitively laid down for the more limited field 

 of the theory of colour-vision was, a quarter of a century later, brought 

 out again by Johannes Miiller under the name ' the law of specific energy 

 of the organs of sensation ' (' Gesetz der specifischen Energie der Sinnes- 

 organe '), and proved to hold good for the whole field of physiology. 



It is little known that the insight of Thomas Young had even a greater 

 depth. He had already explained that the confusion of colours, which his 

 contemporary Dalton made, was a consequence of the absence or paralysis 



