96 



Fis. II. Internal View of App: 



Fig. III. Cro.ss seftion of the apparatus to show the position of the plant and its relation to the 

 microscope and the glass rod; \"C, velvet collar sealing the aperture through which the inicroscope 

 ■works; I, the iris diaphragm; SG, the glass rod; T, tape covering the ghiss rod to make it light 

 proof; P, the plant, BC, the collar which slips over the bottle; K, the bottle containing the saturated 

 solution oi bichromate of potassium; WC, the white cardboard to reflect light into bottle. 



