ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



667 



fits into a corresponding perforation in the rocking-lever D, and can 

 be securely fixed by two milled-lieaded screw.:-. To the underside of the 

 angle-piece is applied a four-sided prism d, carrying on each of two 



RMi 



R Mil 



Fig. 99. 



opposite sides a wing-shaped plate e. These wings e, with the prism/, 

 form an arrangement for receiving in a suitable insertion the rotatory 



Fig. 100. 



object-cylinder b. Fig. 101, which is a frontal section, through the 

 vertical rotation-axis &x, gives further details, the section being so 

 drawn as to show also the horizontal rotation-axis y y, which intersects 

 the vertical axis £ z in a point of the object cylinder axis. The author 



2 Y 2 



