Lives of the electricians

by William T. Jeans

In 1872 Mr. Culley, the engineer-in-chief of the Telegraphic system of the United Kingdom, stated that in order to increase the number of messages which could be sent through the wires in a given time, a very large use had to be made of the Wheatstone automatic instrument, which was in use by the Electric Company before the transfer to the Government. There were only four circuits then; but in the two years following the transfer fifteen circuits were supplied with that apparatus. In addition to these automatic circuits for ordinary business, the Telegraph Department had also fitted up with that system what they called the Western News circuit running from London to Bristol, Gloucester, Cardiff, Newport, Exeter, and Plymouth, the news being then sent to all these places simultaneously, and at the rate of fifty to fifty-five words a minute. A very great improvement had also been effected, at considerable expense, in the single-needle instrument. A very large number of inventions had been brought before the Department, and it might have been hoped that very considerable advantage to the public would have arisen from the breaking up of the monopoly of the Companies and the private interests which almost all the officers had in perpetuating the form of some old instrument. But Mr. Culley had to report that not in any one instance had any apparatus or system of signalling of practical value been laid before him. One system only had been of such a nature as could possibly have any value, and he said that one would have required fully ten years to mature before it could be brought out.

Professor Wheatstone lived to see 140 of his automatic instruments in use. In 1872 he applied to the Judicial Committee of the Privy Council for a prolongation of his patent; and it being then stated that he had received £12,000 in 1870, when the transfer of the telegraphs took place, the Government agreed to pay him an additional sum of £9,200 in six yearly instalments as compensation for his patent rights.

In 1879 Mr. Preece, the electrician to the Post Office, said that the automatic transmitter “is an instrument of great delicacy and great power; it is now used to an enormous extent in this country, and it is one that we are improving every day. For instance, while about this time last year we were able to transmit all our news to Ireland at the rate of 60 words a minute, we are now doing it with ease at the rate of 150 words a minute; and with the improvements which we have now in hand, we shall be able next year to transmit nearly 200 words a minute.” This expectation was realised. Although experience suggested improvements in nearly every part of the apparatus, the leading principles remained the same. In 1885 Mr. Preece gave the following account of the successive stages of the progress made: it was capable of transmitting in 1877, 80 words per minute; in 1878, 100; in 1879, 130; in 1880, 170; in 1881, 190; in 1882, 200; in 1883, 250; in 1884, 350; in 1885, 420. It thus appears that if three men were speaking at the same time, one of Wheatstone’s automatic instruments could transmit the three speeches in the same time that they were spoken, the instrument transmitting three times as fast as one man could speak.

Towards the close of the first half century of the existence of the telegraph, the Wheatstone automatic transmitter achieved the great feat of transmitting 1,500,000 words from London on the night when Mr. Gladstone explained his plan for giving self-government to Ireland, On that occasion (April 8, 1886) one hundred Wheatstone’s perforators were used in the Central Telegraph Office in London to prepare the messages. Thirty of these perforators punched six slips at once, thirteen punched three slips at once, thirty-one punched two slips at once, and twenty-six punched single slips. The largest number of words previously transmitted in one night was 860,000; and to give some idea of what 1,500,000 words represent, it may be added that if an average quick speaker like Mr. Gladstone were to speak without any stoppage for a week, night and day, that would just be about the number of words that he would utter, or that another person could read aloud.

FOOTNOTES:

[7] The keeper or armature is the piece of iron which is placed across the ends or poles of a horseshoe magnet.

CHAPTER IV.

“A name, even in the most commercial nation, is one of the few things which cannot be bought. It is the free gift of mankind, which must be deserved before it will be granted, and is at last unwillingly bestowed. But this unwillingness only increases desire in him who believes his merit sufficient to overcome it.”—Dr. Johnson.

From the two preceding chapters it appears that Professor Wheatstone was not only the inventor of the first electric telegraph used in England, but that he at last invented the most perfect transmitter of telegraphic intelligence. He not only nursed it from its birth, but reared it to maturity; and the period that elapsed between his first and last invention of telegraphic apparatus was exactly twenty-one years. But this was not enough for his versatile mind to accomplish. He had worked successfully as an inventor for seventeen years before his first telegraph was invented, and he continued to work at his favourite subjects for seventeen years after his last great telegraphic invention. Having confined our attention in the last two chapters almost exclusively to the progress of the telegraph, it remains for us to follow the inventor into the bye-paths which he now and then delighted to tread, as well as to follow his course during his latter years along the highway of electrical science in which his genius appeared to find its most congenial exercise.

It has already been explained that in the early years of his electrical researches, he was one of the first men in England to draw attention to the thermo-electric pile originally constructed by Nobili and Melloni in 1831; it consisted of a bundle or pile of small plates of bismuth and antimony, which when heated converts heat into electricity. By connecting this pile by coils of wire with a galvanometer (a movable needle) it becomes a delicate means of indicating minute changes of temperature, the electricity generated by heat moving the needle. This instrument can be affected by the warmth of the hand held several yards away from it; and it is believed that without it, as a thermoscope, the important discoveries respecting radiant heat made by Professor Tyndall and others would have been impossible. It has even been found possible by means of this sensitive apparatus to estimate the amount of radiant heat emitted by insects. In 1837 Professor Wheatstone predicted great results from the thermo-electric pile as a source of electricity, and in 1865 he constructed a powerful thermo-electric battery of that description. It was composed of sixty pairs of small bars, and it was stated that by its action “a brilliant spark was obtained, and about half an inch of fine platinum wire when interposed was raised to incandescence and fused; water was decomposed, and a penny electro-plated with silver in a few seconds; whilst an electro-magnet was made to lift upwards of a hundredweight and a half.” This thermo-electric battery may be said to have electrified the imaginations of men of science, who saw visions and dreamt dreams about its future. For instance, it was suggested that “like windmills, thermo-electric batteries might be erected all over the country for the purpose of converting into mechanical force, and thus into money, gleams of sunshine which would be to them as wind to the sails of a mill.” Many other attempts have been made to construct a thermo-electric pile capable of being used as a generator of electricity instead of the voltaic battery or the dynamo; and although much progress was made in later years, the difficulty in the way, as Lord Rayleigh observed in 1885, was the too free passage of heat by ordinary conduction from the hot to the cold junction.