Plate IX. 



Microscopic Comparinq Apparatus .- 



J* 



JL MaOc Sfre7f. 



Hails. 



Front Elevation 



H*Ui 



Elevation. ((MccpzccrTer/ulhize J Plan. 



Contact Apparatus. 



D 



r 



3 



Contact Pieces for Spherical Ends . 



*!$) ^ 



I \ enlarged. 



ILB.LcLel* 



Contact Pieces for Square Ends 



