milliammeter
Date1900-1920
Inventory Number0470
ClassificationAmmeter
Subject
Maker
Robert W. Paul Instrument Company
1891 - 1919
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Place of Use
Dimensions6.9 × 11 × 14.5 cm (2 11/16 × 4 5/16 × 5 11/16 in.)
Material
DescriptionMilliammeter consisting of a rectangular black cast iron case with a fan shaped cut out with glass over scale. There is a raised circular portion over the internal movement with one screw and one knob with an arrow. A rectangular plate on the circular section is marked "CLAMP FOR TRANSIT / DEPRESS AND TURN." There are two binding posts at the bottom.
The scale reads scale from 0-25, in increments of 5, with a mirror and a knife edged pointer.
Marked in handwritten lettering under the scale "PAUL, LONDON," most likely referring to the Robert W. Paul Instrument Company in London, which specialized in electrical instruments.
The scale reads scale from 0-25, in increments of 5, with a mirror and a knife edged pointer.
Marked in handwritten lettering under the scale "PAUL, LONDON," most likely referring to the Robert W. Paul Instrument Company in London, which specialized in electrical instruments.
Signedhandwritten under scale: PAUL, LONDON
Inscribedhandwritten under scale: MILLIAMPERES / IY-849 / PAUL, LONDON
on raised circular portion: P L / UNIPIVOT / CLAMP FOR TRANSIT / DEPRESS AND TURN
FunctionMeasurement of small currents. The "unipivot" design was developed by Paul, increasing sensitivity and decreasing friction relative to other ammeters with multiple moving parts.
ProvenanceFrom Department of Physics, Lyman Laboratory, Harvard University [1965, marked with physics 3 blue triangle].
Weston Electrical Instrument Corporation
Date: circa 1911
Object number: 0525
Robert W. Paul Instrument Company
Object number: 2012-1-0013
Peter & John Dollond
Date: circa 1768
Accessories: Aquatic and Wilson attachments; 2 lenses to fit either ; 2 silverplated Lieberkuhns with lenses ; stage forceps ; tweezers ; 3 bone slides ; 1 brass framed glass slide for Wilson
Object number: 1007
Weston Electrical Instrument Corporation
Date: 1890-1900
Accessories: shunt apparatus (0417b)
Object number: 0417a