T. ROSS'S MICROSCOPE 



197 



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

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



FIG. 159. The model by T. Koss (1862). 



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, 



