SUBMARINE TELEGRAPHS.
TO THE EDITOR OF THE MORNING POST1
SIR,—With reference to the notice on the submarine telegraph which appears in your impression of to-day,2 I hope you will permit me to say that my knowledge of the subject3 at present extends simply to the fact that I have submitted india-rubber and gutta percha4 covered wires to a test of extreme severity, and have found that insulating powers of both substances excellent. I do not now know which of them is best, and I have never made an experiment with either of them in which hydraulic pressure was applied.5 —I am, sir, your obedient servant,
14th March, 1859. | JOHN TYNDALL.
Morning Post, Wednesday, March 16, 1859
TO THE EDITOR OF THE MORNING POST: Algernon Borthwick (1830–1908). Borthwick was appointed editor of the Morning Post following the death of the previous editor, his father Peter Borthwick (1804–52), in 1852. The editorial line of the paper was conservative (ODNB).
the notice on the submarine telegraph which appears in your impression of to-day: ‘Submarine Telegraph’, Morning Post, 14 (March 1859), p. 3.
my knowledge of the subject: Tyndall was cited in the article as having given assurance to the company producing a new process of insulation for the telegraph wire (Messrs. Silver, of Cornhill and Bishopsgate-street) that india-rubber would be able to withstand the hydraulic pressure under water.
gutta percha: A substance that resembles rubber, derived from a type of Malaysian tree of the Palaquium genus (OED).
I have never made an experiment with either of them in which hydraulic pressure was applied: According to the article, Tyndall had stated that he had performed tests on more sensitive wiring with no problems with the coating. See also letter 1755, n. 2.
Please cite as “Tyndall1599,” in Ɛpsilon: The John Tyndall Collection accessed on