I
Note On the Contributions of Fleeming Jenkin to Electrical and Engineering Science. by Sir William Thomson, F.R.S., LL D., etc., etc.

In the beginning of the year 1859 my former colleague (the first British University Professor of Engineering), Lewis Gordon, at that time deeply engaged in the then new work of cable making and cable laying, came to Glasgow to see apparatus for testing submarine cables and signalling through them, which I had been preparing for practical use on the first Atlantic cable, and which had actually done service upon it, during the six weeks of its successful working between Valencia and Newfoundland. As soon as he had seen something of what I had in hand, he said to me, ‘I would like to show this to a young man of remarkable ability, at present engaged in our works at Birkenhead.’ Fleeming Jenkin was accordingly telegraphed for, and appeared next morning in Glasgow. He remained for a week, spending the whole day in my class-room and laboratory, and thus pleasantly began our lifelong acquaintance. I was much struck, not only with his brightness and ability, but with his resolution to understand everything spoken of, to see if possible thoroughly through every difficult question, and (no if about this!) to slur over nothing. I soon found that thoroughness of honesty was as strongly engrained in the scientific as in the moral side of his character.

In the first week of our acquaintance, the electric telegraph and, particularly, submarine cables, and the methods, machines, and instruments for laying, testing, and using them, formed naturally the chief subject of our conversations and discussions; as it was in fact the practical object of Jenkin’s visit to me in Glasgow; but not much of the week had passed before I found him remarkably interested in science generally, and full of intelligent eagerness on many particular questions of dynamics and physics. When he returned from Glasgow to Birkenhead a correspondence commenced between us, which was continued without intermission up to the last days of his life. It commenced with a well-sustained fire of letters on each side about the physical qualities of submarine cables, and the practical results attainable in the way of rapid signalling through them. Jenkin used excellently the valuable opportunities for experiment allowed him by Newall, and his partner Lewis Gordon, at their Birkenhead factory. Thus he began definite scientific investigation of the copper resistance of the conductor, and the insulating resistance and specific inductive capacity of its gutta-percha coating, in the factory, in various stages of manufacture; and he was the very first to introduce systematically into practice the grand system of absolute measurement founded in Germany by Gauss and Weber. The immense value of this step, if only in respect to the electric telegraph, is amply appreciated by all who remember or who have read something of the history of submarine telegraphy; but it can scarcely be known generally how much it is due to Jenkin.

Looking to the article ‘Telegraph (Electric)’ in the last volume of the old edition of the ‘Encyclopaedia Britannica,’ which was published about the year 1861, we find on record that Jenkin’s measurements in absolute units of the specific resistance of pure gutta-percha, and of the gutta-percha with Chatterton’s compound constituting the insulation of the Red Sea cable of 1859, are given as the only results in the way of absolute measurements of the electric resistance of an insulating material which had then been made. These remarks are prefaced in the ‘Encyclopaedia’ article by the following statement: ‘No telegraphic testing ought in future to be accepted in any department of telegraphic business which has not this definite character; although it is only within the last year that convenient instruments for working, in absolute measure, have been introduced at all, and the whole system of absolute measure is still almost unknown to practical electricians.’

A particular result of great importance in respect to testing is referred to as follows in the ‘Encyclopaedia’ article: ‘The importance of having results thus stated in absolute measure is illustrated by the circumstance, that the writer has been able at once to compare them, in the manner stated in a preceding paragraph, with his own previous deductions from the testings of the Atlantic cable during its manufacture in 1857, and with Weber’s measurements of the specific resistance of copper.’ It has now become universally adapted — first of all in England; twenty-two years later by Germany, the country of its birth; and by France and Italy, and all the other countries of Europe and America — practically the whole scientific world — at the Electrical Congress in Paris in the years 1882 and 1884.

An important paper of thirty quarto pages published in the ‘Transactions of the Royal Society’ for June 19, 1862, under the title ‘Experimental Researches on the Transmission of Electric Signals through submarine cables, Part I. Laws of Transmission through various lengths of one cable, by Fleeming Jenkin, Esq., communicated by C. Wheatstone, Esq., F.R.S.,’ contains an account of a large part of Jenkin’s e............