638 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



be used in conjunction with arc lamps working with a current of about 

 10 amperes. Any excess of power may easily be reduced with the aid 

 of an iris-diaphragm or by increasing the distance of the lamp. Nemst 

 lamps of 250 to 500 c.p. or the Liliput lamp should be used in 

 conjunction with an illuminating lens and a screen on a stand. With 

 the arc lamp and also with the Nernst and Liliput lamps it is advisable 

 to protect the eyes by screening off all stray light with the aid of a 

 hood. Nernst and Liliput lamps may by means of an ordinary wall 

 plug -be worked from the house supply service, but purchasers should, 



Fig. 102. 



when ordering, state in each case the voltage and the nature of the 

 current, i.e. whether it is continuous or alternating, the frequency being 

 likewise indicated in the latter case. When gas is available, the 

 illuminating appliances illustrated in fig. 98 may be employed. Some 

 of the Reichert reflecting condensers have been recently modified, so 

 as to give greater light-transmitting power, and to be suitable for 

 special purposes. 



The Reflecting Condenser, fig. 99, is, without any need of special 

 adaptation, attachable to any Microscope provided with a sufficiently 

 large cylinder diaphragm or Abbe condenser. It is provided with two 



