Report on the magnetic observations made at the University of Groningen during the total solar eclipse of May 17, 18, 1901

W. Haga
1901 Journal of Geophysical Research  
At the request of Dr. van Rijckevorsel, I have made in the laboratory of the University of Groningen, during the night between •7-•8 May, observations of the variations of declinations and of the horizontal intensity. The laboratory is quite free from iron, and lies in a garden far from the railway, canals, and frequented streets. In Groningen there are no electric car lines nor electric plants, hence we are undisturbed by stray or "vagabundirende" currents. The variations of declination were
more » ... declination were observed by means of a unifilar magnetometer of Kohlrauseh; scale and telescope were at a distance of 4•9. 7 e. m., so that a change in the direction of the magnet of i t gives a displacement of the image of the scale of 2.smm. The telescope had an aperture of 40rnrn, a focal length of 450 ram, and a magnifying power ooe 55 times-the readings v•ere accurate, at least to o.•m•n, now and then O.O$ mm being estimated.
doi:10.1029/te006i003p00128 fatcat:2ued5bg3m5goxpl2jz5zfkulzq