44 Journal of the Mitchell Society \^May 



position. This upright shadow on the retina, however, makes 

 us think that the object throwing it is inverted, for the shadow 

 certainly "looks" inverted to us. But we know that the object 

 throwing the shadow is upright, and it follows in consequence 

 that the retinal images of upright objects are inverted. In using 

 this apparatus the eye must not be focussed on the pin, or the 

 hole F, but on something distant, like the clouds or the twigs 

 of trees between the observer and the sky. 



Chapel Hill, IST. C. 



