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SUMMARY OF CURRENT RESEARCHES RELATING TO 
has to he lowered by rack-and-pinion motion before the condenser can 
he thrown out (Reichert method). Since, in working without condenser, 
cylinder diaphragms are generally necessary, these have also to be 
introduced. These operations require time and prevent the possi- 
bility of observing the immediate consequence of the change of illumi- 
nation on the preparation. 
The arrangement which the author has devised is free from these 
two disadvantages. It requires no reconstruction of the stand and no 
movement of the illuminating apparatus in the line of the optic axis. 
Fig. 59. 
In fig. 59 the apparatus is seen as attached to the stand. In fig. 60 it 
is shown by itself as seen from above. 
p} The socket S, of the size to fit into any spring socket of a Zeiss 
stand, carries on its lower flange a projecting piece L, which is bored 
through its other end for the reception of the pin Z. About this pin as 
vertical axis turns the frame R, to which is attached the condenser 
system C which is movable downwards to a stop about a horizontal 
axis Q. The movements about this axis and also about the vertical 
axis Z are both effected by the lever H. 
