232 



SIWIMAKY nv r['|;|;i,\T I; KSK A R| 'I I Ks RELATING TO 



claimed. The difference is in the limb which supports the tube; the 

 limb being solidly attached to the base and carrying the rackwork at its 



Fig. 37. 



upper end. The tube movement is independent of that of the objective. 



Fig. 37 shows model No. 2481 in section. Here the nicols rotate 



while the stage is fixed, and this arrangement gives a means of suppress- 



