The Smithsonian Institution has made numerous invaluable contributions to the Yokogawa Instrument　Collection, some of which we will be introducing in these pages. Based in Washington D.C, the Smithsonian Institution is an aggregate of 14 museums that are run by 6,000 staff and an equal number of volunteers. Its museums cover the entire spectrum of human knowledge and the structures housing their collections are inspiring both in the architectural and the historical sense.

Smithsonian Castle. Construction completed in 1855

Kelvin Balance (ampere balance)
Manufactured by JW Queen and Company, USA in 1900
(30 A, 19 x 54 x 27 cm, 22 kg)

This instrument measures the absolute value of a current by weighing the attractive and repulsive forces acting between dual coils. The instrument rests on a marble base.

Ammeter
Manufactured by Weston Electrical Instrument Corporation, New Jersey, USA
(10 A, 170 mm diameter x 100 mm, 4 kg)

This was a switchboard ammeter that was made in the 1880s. In those days, large meters such as this were mounted in a row on a marble switchboard. The embossed arabesque patterns on the instrument face are particularly beautiful.