| name of the apparatus | Thomson's reflecting galvanometer |
| classification | electricity & magnetism |
| name on the ledger | Sir Thomson's reflecting galvanometer |
| purchased year | 1891 |
| demander | unknown |
| maker | Elliott Brothers, London |
| seller | MIYATA Tozaemon |
| price | 93 yen 50 sen |
| In this galvanometer, a short magnetic needle and a light round mirror are suspended. As an electric current passes through the coil, the needle and the mirror rotate, and its rotation angle can be measured by a reading telescope. The upper arc magnet erases the earth magnetic effect so as to return the magnetic needle to the original direction. This galvanometer was invented by W. Thomson at 1857, in order to detect the feeble signal of the Atlantic telegraph cable. | |