Undemagnetizable

a. (UN-¹ 7 b.)

1

1876. S. Kensington Mus. Catal., No. 1703. Pair of Undemagnetisable Coils, designed in 1866.

2

1882. Crystal Palace Internat. Electric Exhib. Catal., 17. Brittan’s Undemagnetizable Needle.

3