Literary Notices. xxv 



spot of clearest vision. This is especially true of the eye when accom- 

 modated to darkness. 



The first set of experiments with a mixed (blue) hght were so con- 

 ducted that a small disk was placed on a black background and faintly 

 illuminated, after which it Avas moved in a lateral direction till a point 

 was found where it was no longer visible. The sensitiveness was de- 

 termined in terms of the threshold value of the fovea. For about two 

 degrees at the center the sensitiveness was found to be nearly constant, 

 beyond which distance it increased rapidly to beyond five degrees — 

 most rapidly on the nasal side of the retina. 



The second set of experiments shows that red light is an exception 

 as its effect diminishes from the fovea while the increase is more 

 marked in the case of blue than of yellow light. The author suggests 

 that as the red light does not affect the rods while other colors do, and 

 the rods are more numerous toward the periphery, the increase m one 

 class of colors is to be ascribed to their superior efficiency on the rods 

 and the rate of increase will depend on the " rod-valence." 



For numerous interesting details see the original. c. L. H. 



The Psjcliology of Inrention.^ 



The paper by Professor Royce under the above caption is acces- 

 sible to most of our readers but a summary of the conclusions and of 

 the methods suggested for investigation may interest those who are not 

 psychologists by profession. 



It is stated that "important inventions do not occur, in general, 

 except under particular social conditions", and the individual varies 

 more when variation is encouraged, when independence, private enter- 

 prise, is favored by social environments. Accordingly, children in the 

 country or isolated from school routine often show greater inventive- 

 ness in their games than do children early submitted to the routine of 

 large schools. In history also periods of great individualism have been 

 periods of great inventiveness, as during the Renaissance and Revolu- 

 tionary period. Professor Royce has endeavored to produce in an ex- 

 perimental way conditions which in a small way should simulate those 

 which form the basis for the reaction between the subject and the en- 

 vironments tending to originality. 



The experiments consisted in requiring the unbiased subjects to 

 draw a series of designs which should not imitate anything; at first 

 hastily, and then deliberately. Then the same subjects were requested 



1 Psych. Rev. V, 2. March, i{ 



