PLATE X. 



Fig. 42. 



Pig. 44. 



Diagram to show the arrangement for examining otsects by 

 transmitted light p. 18. 



Mr. Wenham's original arrangement 

 of the binocular microscope, p. 11. 



Fig. 43. 



Fig. 45. 



Diagram to illustrate the arrangement for examination 

 by reflected light, p. IS. 



Arrangement of prism a in Nachet's binocular 

 microscope, p. 11. 



[To face page 20. 



