PLATE 15. 



J "^fw * ' 



Zeiss microscope stand 11^ 



This form of microscope and that represented on plate 16 are the two patterns used princi- 

 pally in the Laboratory of Plant Pathology, U. S. Department of Agriculture. The 

 objectives are apochromatic. and have proved very serviceable. In carrying do not grasp by 

 any part above the level of the stage, as this brmgs an undue weight upon the tine adjust- 

 ment. Seize by the base. 



