8 4 



BINOCULAR MICROSCOPES 



[CH. Ill 



piece for use on any monocular microscope. The prisms divided the 

 light equally and it was sent up through tubes parallel with the main 



FIG. 52. WENHAM'S BINOCULAR MICROSCOPE. 

 (From Carpenter). 



A Section of the microscope with the two converging tubes. By pulling 

 out the draw-tubes the oculars are separated for the correct pupillary distance 

 of each observer. 



L R The axes of the left and right tubes. 

 * a The prism which divides the light from the object. 



c b The field lenses of the two oculars. 



B Enlargement of the dividing prism. 



a, b, c, d Path of the light in the prism for the left eye. 



As shown, the light to the right eye extends straight upward. This ar- 

 rangement is limited to rather low powers. 



tube of the microscope, but, of course, separated the proper distance 

 for the two eyes. In the words of President F. P. Barnard of Colum- 

 bia College, New York, "This binocular eye-piece works with objec- 

 tives of all powers with perfect equality of illumination in both fields." 



