= 28 



in advanced microscopic work, that it now justly forms an essential adjunct to 

 all the larger stands intended for scientific research. 



Particulars regarding the construction and L application of tliis apparatus 

 may be found in the detailed directions for use, which are issued with each 

 stand fitted with the ABBE illuminating apparatus. 



Figr. 9. 



a: ABBE Illuminating' Apparatus with ordinary Condenser No. 25'; r: screw for clamping the 



condenser in the sliding sleeve; p: knob of iris-diaphragm No. 23; *: ordinary Condenser Xo. 26; 



c: Cylinder-diaphragm No. 21. (Full Size.) 



The various lens systems Condensers which are adapted for use with 

 the ABBE illuminating apparatus are all mounted in such a manner that they 

 can be conveniently inserted into the sliding sleeve of the apparatus and may, 

 if necessary, be clamped in any position. See Fig. 9. Since 1886 we have invariably 

 added an iris-diaphragm, which facilitates a very gradual variation of the aperture. 



We only supply the ARBE illuminating apparatus with one 



of the follotving stands : I, III and IV. Its adaptation to other stands 



- if at all practicable - - must be carried out in our own works. 



The various diaphragms, condensers, &c. used in connection with the appar- 

 atus are, however, supplied separately as follows: 



