Signedunsigned
Inscribedon metal strip: PAT MAY 16 1893 No. 497482;
on left block: 64146
on right block: 20 AMP;
painted in white on wood: 33B;
FunctionAccording to card, the shut is pivoted with bolts rather than wing bolts for current conductors, which would indicate it was used with a switchboard meter.
ProvenanceFrom the Jefferson Physical Laboratory, Harvard University. Was used for teaching Physics 3 class; and from Pierce Hall, Engineering School, Harvard University.