Portable Galvanometer


Portable Galvanometer


Physics Demonstration


Physical Description
Object comes in a wooden box. Box has a hinged lid and can be locked. Lock is made of metal with two screws on the face holding it to the side of the box. A leather strap is attached to the side of the box by the lock. There is a parchment tag attached to the leather strap. The strap connects to the box on two opposing sides with each side using two metal screws with washers to hold an end of the strap to the box. There is a brass placard on top of the lid of the box. On one side of the bottom of the box there are two numbers printed. The bottom of the box has four feet. There is a detachable curved metal piece that has cardboard slotted into one side. The cardboard has numbers written on it with tick marks below certain numbers. The actual instrument consists of a hinged scope affixed to a metal base. A knob behind the scope rotates a mirror that is positioned below the scope. The scope has a metal circular piece attached to the top. Two metal screws with holes are mounted behind the hinge of the scope. A brass knob is attached to the metal base and contains a water bubble. A solid, locking white oak case with leather handle encloses a elctrical-telescopic instrument.

Functional Description
The box serves to protect the scope along with holding the metal measuring card. The knob on the metal base serves as level. The knob on the back of the scope is presumed to rotate a hanging mirror inside the scope. The exact function of the scope is unknown since it appears that it requires power (electrical) to function properly.
The case is opened 180˚ and the whole unit is leveled using the bubble level (the brass bullseye) on the rear part of the apparatus. The curved scale is attached to the inside of open top to use as a target and the telescopic eyepiece is raised up from the box.  Two binding posts at the front of the instrument must take electrical leads to provide (variable) voltage or current to the sample cell, which appears to be the central black cylinder.  Somehow the electricity will cause light to be refracted differently and the split prism below the eyepiece can then be used to read a number from ±17 (units?) to be read.


Gary Spikberg, Andrew Merdzinski, Andrew Stanley, Nick Lesko with additions by Steven A. Walton


Collection of Historic Scientific instruments at Harvard: portable galvanometer with telescope




physical object




Serial Number: 154126
Exterior of Box top: G3 | MCMT-8885
Exterior of Box bottom: 2900 41481

Physical Dimensions

Open: 45.5cm x 18.5cm x 10cm Closed: 22.5cm x 12cm x 10cm


wood (white oak), metal, glass, plastic, leather, cardboard


Leeds & Northrup Company, Philadelphia, PA


[top, riveted plate] PATENTED | LEEDS & NORTHRUP CO. | PHILADELPHIA | SER. NO. 154126 | MADE IN USA
[top, plastic cap] LEEDS & NORTHRUP CO. | PHILADELPHIA
[on lock] AD
[case top, screwed on brass plate] MCMT-8885
[case side, labels] 2900 | 41491
[scale] [black]17 to [red] 17 by 0.1 | LEEDS & NORTHRUP CO.

History of the Object

Leeds & Northrup was founded in 1899 by Morris F. Leeds, and reincorporated as "Leeds & Northrup Co." in 1903, so this must date from after that. The Michigan College of Mining Technology (MCMT) became Michigan


Fisher Hall, physics storage


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Gary Spikberg, Andrew Merdzinski, Andrew Stanley, Nick Lesko with additions by Steven A. Walton, “Portable Galvanometer,” Michigan Tech Inventory of Historic Scientific Instruments, accessed March 4, 2021, https://ihsi.omeka.net/items/show/178.

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