ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 555 



stand made, and equally useful for biological examinations and for 

 the more special examinations of test objects. Hitherto the instrument 

 could only be obtained in America, which was necessarily a drawback 

 to its use in England. Messrs. Watson have now, however, undertaken 



Fig. 95. 



its manufacture (with some modifications), their instrument being 

 shown at fig. 95. 



The fig. shows sufficiently the general form of the instrument: 

 its special feature is that the substage bar and mirror bar are 

 fixed to separate collars, so that they swing separately below and 

 above the stage, the movement of each being independent of the 



