19 
as Professor of Natural Philosophy, when all nations and learned 
bodies sent representatives to do him honour. In later life, indeed, 
honours were showered upon him. He was President of the Royal 
Society ; an original member of the Order of Merit ; he held the 
Prussian Pour le Mérite, the French Legion of Honour ; he was a 
Privy Councillor, Chancellor of his University, a member of every 
foreign Academy, and an honorary graduate of almost every Uni- 
versity. Yet, withal, he was modest, simple, and lovable to an 
extreme degree, and anyone who was fortunate enough to enjoy 
his intimacy received an enhanced idea of the possibility of human 
nature. Though at the Leicester meeting of the British Association 
in 1907 he seemed to show his usual surprising activity of mind 
. and body, in a few months he sank under the influence of a chill, 
and was buried in Westminster Abbey with national honours. 
| After the lecture, refreshments were served in the Small Hall. 
A collection of scientific exhibits were on view. 
Friday, November 6th. Mr. P. E. Vizard, Vice-President, in 
the chair. 
Dr. F. Edridge-Green gave a lecture on ‘‘ Colour-Blindness 
and Colour-Perception.’’ The lecturer showed by coloured 
lantern slides the nature of the mistakes commonly made by colour- 
blind persons. There are two classes of colour-blind cases :— 
I. Those in which the colour spectrum is shortened at one or both 
ends ; that is, in which light of extreme wave lengths, commonly 
visible, gives no impression at all upon the eye ; and (2) those in 
which light perception is normal, but colour perception defective. 
Colour perception is a matter of degree, varying from those rare 
cases where only one colour is recognised to the normal case where 
six colours can be distinguished, viz., red, orange, yellow, green, 
- blue, and violet. The indigo of Newton, though generally believed 
by most persons to be recognisable, is really only distinguished as 
separate colour by one person in several thousands. The common 
form of colour-blindness, the trichromic, in which red and green 
are confused, is the most important, as such persons are obviously 
unsuited to be railwaymen or seamen. Many persons are unaware 
of their defect, as was shown at this meeting by the fact that several 
“members present found themselves incapable of passing the simple 
lantern tests which the lecturer applied. Much interest and some 
amusement were caused by the answers given by these members. 
In some cases, for instance, where a vivid green was shown by 
__ the lantern, the colour-blind person stated it to be red. By means 
bi, 
~s 
