Fig. 1. Atmospheric-electric cabin at right, showing starboard wall and entrance 



Fig. 2. Looking down on roof of atmospheric-electric cabin just for- 

 ward of the mainmast. Forward of the cabin is a dome used for 

 magnetic measurements, and forward of the dome is the bridge. 

 At the stern rail may be noted both eye-reading and recording 

 apparatus for potential-gradient measurements 



Fig. 3. Ion counter DTM No. 1 0C1) for measurement of small-ion 

 content of the atmosphere. The apparatus projects through the 

 roof and_is uncovered during use 



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