In dry weather the electric potential in the atmosphere is normally positive relative to the earth, and increases with the height.
After two hours' exposure, it is wrapped round a frame supported in a given position relative to Elster and Geitel's dissipation apparatus, and the loss of charge is noted.
The planets were shown to have visible disks, and to be attended by satellites whose distance and position angle relative to the planet it was desirable to measure.
These furrows have apparently been cut in situ with a very accurate engine; for not the slightest departure from parallelism can be detected in any of the movable webs relative to the fixed webs.
If the errors of the rectangular co-ordinates of these lines are known, the problem of determining the co-ordinates of any star-image on the plate becomes reduced to the comparatively simple one of interpolating the co-ordinates of the star relative to the sides of the 5 mm.
