细节
A 19th-Century galvanometer,
by Siemens Bros & Co London, the coil mounted between two lacquered-brass pillars and enclosed within a glazed cylindrical dust cover, on mahogany base -- 15in. (40cm.) high
by Siemens Bros & Co London, the coil mounted between two lacquered-brass pillars and enclosed within a glazed cylindrical dust cover, on mahogany base -- 15in. (40cm.) high