240 Transactions of the Society. 



interest of all these experiments lies in the experimental proof of 

 what he calls the summit of his theory of microscopical vision, 

 viz. : that all microscopical images of fine structures are not direct 

 dioptrical images, but secondary images produced by the inter- 

 ference of pencils into which, by diffraction in the structure, the 

 incident beam of light is resolved. 



