Caml. Phil. Sor Proc. Vol III. Part V. 



Plwt^ IV. 







Fip-. I 



i,;', / ShowirKj spider 

 Spider lines ^l'y.\li, lines rrvinioMredj 



Gradivally separated '^ , ' / 



Pier. 5. 

 Staae IMicrometer 



Mtcroineter att-ached as a Microscope to 

 measure power of rnirvi-aMire objectvve/. 



DT Royston Pitfott. Pel. 



