BOSS'S RECENT MICROSCOPES 



231 



The principal difference between the two instruments is in their 

 respective stands. The one shown in fig. 184 gives a wider .spread 

 to the tripod base than usual, securing greater stability ; but this does 

 not involve great space in packing, because the hind ' toe ' of the 



FIG. 184 Ross's new (tripod) bacteriological microscope (1898). 



tripod is made to fold forward between the two fixed front toes when 

 not in. use. 



The other similar instrument is 011 a circular foot, to which is 

 screwed a stout supporting pillar ; the upper part is attached to 

 this by a substantial compass- joint ; but the pillar is fixed on the mar- 

 gin of the ring, thus bringing the whole weight centrally upon the 



