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This horizontal galvanometer by Daniel Davis, Jr. sits
on the desk next to me as I write. Across the top is written, in gold printing,
"Daniel Davis Jr. Boston." It is a little over 16 cm high and about 22
cm in width. The circular brass base is confusing, as the 1842 and 1851
editions of the Manual of Magnetism show the tripod brass base of
the example below.
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| This horizontal galvanometer at Allegheny
College in Meadville, Pennsylvania, has had its coil and magnet repainted,
thus covering up Davis's name.
The catalogue copy for the 1842 and 1851 editions of the Manual reads: If the wire is carried many times around the needle,,,, the power of the instrument is much increased, as each turn of the wire adds its influence; provided the wire is not so long or of so small a size as to be unable to convey the whole of the current. The instrument thus becomes a delicate test of the presence of a current of electricity." The instrument cost $6.00 with the tripod base. |
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