direct current milli-voltmeter
Date: circa 1914
Inventory Number: 0278
Classification: Voltmeter
Dimensions:7.5 x 14.5 x 17 cm (2 15/16 x 5 11/16 x 6 11/16 in.)
storage: 17 x 19 x 10 cm (6 11/16 x 7 1/2 x 3 15/16 in.)
Accessories: multiplier in case of instrument; standardization certificate from the Weston Laboratory, Newark, N.J. Feb.1914 on lid of wooden case
DescriptionWeston Standard Model 1. A moving coil meter consisting of a fan-shaped metal case (copper-colored) on a rectangular wooden base. The case has a window near its outer rim, with a scale in black with a white background following the arc-shape of the rim, and a reflecting band underneath the scale. There are numbers above and below the scale. The ones above are black with zero at the center and going to up to 100 in both directions; those below the scale are in red with zero at the center and going up to 10 in both directions. At the other end of the box is a round window that shows a moving coil to which the needle that goes over the scale is attached.
The outer metal case is removable and a thread of red felt marks its contour over the wooden base. The base has two electrical connectors on its lower corners, one of which is marked (+). There is a button above the connector marked (+) to switch between ranges of the voltmeter. On one side of the base between the two electrical connectors is a metal screw marked "correction" to adjust the meter's needle.