On the use of Incandescence Lamps, &c. By C. H. Steam. 31 



(2) On moving the switch h from the central position to the 

 right, contact is made with another stud, and the current passes to a 

 second lamp B, mounted on a platform fitting into the suhstage, 



Fig. 3. 



and capable of rotation and lateral adjustment, so that direct or 

 oblique illumination at any angle may be obtained. 



