intensity variometer
Date: date 1908
Inventory Number: 0247
Classification: Magnetometer
Subject:
Maker: Hartmann & Braun AG (1879 - 1999)
User: Department of Physics, Harvard University (founded 1884)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
28.2 × 37.3 × 20 cm (11 1/8 × 14 11/16 × 7 7/8 in.)
Description:
Magnet (missing) on string suspension in cylindrical copper case with glass suspension tube. 4 projecting arms with bar magnets. Arms slotted with scales of 9 - 11 and 9 - 10. Longer arm with telescope and scale.
Tripod base with levelling screws and two perpendicular levers.
Tripod base with levelling screws and two perpendicular levers.
SignedOn base: HARTMANN & BRAUN / Frankfurt A/M. HARTMANN & BRAUN in Cursive, Frankfurt A/M in Italics.
FunctionMagnetic intensity measurements. For determining variations of horizontal magnetic intensity to 1/100 percent.
Variometers are designed to detect changes in the magnetic field. The magnetic field acting on the mirror is set in a way to maximize the effects of a change in the observed magnetic field of the earth. Any changes are then observed by deviations from this reference. The measurements are made by observing the scale through the scope as it is reflected on the mirror.
From the instrument card:
"The four deflection magnets act on a polished plane steel mirror, which is not affected by the variation of declination, as it is deflected at right angles to the meridian."
Variometers are designed to detect changes in the magnetic field. The magnetic field acting on the mirror is set in a way to maximize the effects of a change in the observed magnetic field of the earth. Any changes are then observed by deviations from this reference. The measurements are made by observing the scale through the scope as it is reflected on the mirror.
From the instrument card:
"The four deflection magnets act on a polished plane steel mirror, which is not affected by the variation of declination, as it is deflected at right angles to the meridian."
Curatorial RemarksPhysics Dept. Old Nos.
From Instrument Card:
For methods of observation see Wiedemann's Annalen v.15 p.540 and also D. C. Miller "Laboratory Physics" p.366 (from W. & L. E. Gurley N.Y. Cat (1908) p.32, price $145.
From Instrument Card:
For methods of observation see Wiedemann's Annalen v.15 p.540 and also D. C. Miller "Laboratory Physics" p.366 (from W. & L. E. Gurley N.Y. Cat (1908) p.32, price $145.
ProvenanceFrom the Physics Department, Harvard University. Blue triangle indicates use in Physics 3 in the late 1920's.