CH. IX] ORDINARY MICROSCOPE FOR PROJECTION 263 



FIG. 145. ORDINARY MICROSCOPE FOR PROJECTION. 



This figure is to show how an ordinary microscope can be used for projection 

 if one has an arc lamp and condenser. 



Commencing at the left : 



The supply wires coming to the table switch. 



From the negative pole of the switch one wire proceeds to the negative bind- 

 ing post of the arc lamp, i. e., to the one for the lower carbon. 



From the positive pole of the switch extend two wires for the automatic lamp 

 of the Bausch & Lomb Optical Co. One wire goes to the binding post of the 

 automatic mechanism (the middle post). This means that the automatic 

 mechanism receives current which does not go through the rheostat. The 

 other wire from the positive pole of the switch goes to the ammeter (A), and 

 from the ammeter to the rheostat (R), and from the rheostat to the positive 

 binding post for the arc lamp, i. c., for the upper carbon. 



The arc lamp is shown through the metal lamp-house. The lamp-house 

 appears transparent as it was left in position during only a part of the exposure. 



Following the lamp-house is the triple condenser and water-cell. 



The microscope is bent over in a horizontal position to bring the axis of the 

 objective in line. 



The microscope is clamped to a block which raises it to the right level. 



