Piano Forte Tuners

1848 Scientific American  
The Eleetrle TelelJraph. No. 2. In our last we explained what electro mag 'netism was in a general sense, but in a speci :Jie sense, it is under. stood to relate only to the combination of a piece of horse shoe shaped soft iron surrounded with insulated helices of wire connected with a galvanic battery. The soft iron is only magnetic while under the in fluence of the galvanic current, and is a focus of magnetic power, capable of driving machi
doi:10.1038/scientificamerican10281848-43e fatcat:6347pajctrbcbpge4hffhiprce