Standard resistor no. 4644
Profs. Ayrton and Perry standard inductance
Campbell variable mutual standard inductance no. L-13769
Clark standard element (cell) no. 142
1872
Clark standard cell
Pair of Clark standard cells in one case
Pair of Clark standard cells in one case
1/3 microfarad standard condenser
1892
Clark standard cell no. 1297 by Nalder Brothers and Co.
Standard condenser no. 30510
1911
Standard air capacitor
Pair of turned wooden standards
1880-1920