I MUST confess that I was surprised by Mr. R. E. Baynes' communication, in NATURE, vol. xix. p. 33, that the galvanometer I have proposed in NATURE, vol. xviii. p. 707, has already been described.

ATTENTION has recently been drawn more than once (notably by Sir William Thomson, and by Mr. W. H. Preece and Mr. Kemp) to the advantages offered, in certain cases of the use of the ...