T. ROSS'S MICROSCOPE 



197 



except specially ordered is never made by this firm, but for its 

 qualities and historical relations it is of much interest. It was 



FIG. 159. The model by T. Ross 

 very similar to the model by T. Ross shown in fig. 159. A. Ross's 

 first model had a triangular bar, was monocular, possessed no 

 proper sub-stage, the condenser was attached to the main stage, 



