The invention of the inverted cup insulator

[Trade Journal]

Publication: The Telegrapher

New York, NY, United States
vol. 5, no. 15, p. 117, col. 1-3

[Written for THE TELEGRAPHER.]




IT is strange how little is often known respecting the origin and history of some of the most common and indispensible [sic] indispensable inventions in every day use among us. It is also too often the case that the inventor, who has been the means of conferring incalculable benefits upon his fellow beings, remains in obscurity, unrewarded and forgotten. A striking instance of this kind was recently brought to light in one of our city dailies, in the person of JETHRO WOOD, the inventor of the cast-iron plough, which to-day is an indispensable implement on every farm in America. Yet WOOD, after spending a handsome fortune in the introduction of his invention, and after living to see it universally used throughout the length and breadth of the United States, was permitted to die in extreme poverty, as a reward for having added untold millions to the wealth of his native country.

It is possible to discover more than one instance of a similar character, without going outside the limits of our profession. How many readers of THE TELEGRAPHER are there who can point out the original inventor of the "relay and local circuit," or of the ordinary insulator, in the form of an inverted cup? Without these two inventions the Electric Telegraph would have been almost valueless, and yet how few of the vast number who make daily use of this most wonderful agency either know or care to whom they are indebted for the advanced state of perfection to which it has been brought since its first introduction to the community.

We have before us the first original printed claim, accompanied by drawings, of the now widely known inverted cup, or "umbrella" line insulator, copies of which are on file at the Patent Office at Washington, and in the Astor Library of this city, and an examination of them has led us to make a few remarks upon the general subject of electrical insulation.

It is interesting to observe that there is scarcely a discovery of modern times whose origin cannot be traced backwards, often for many centuries, to some suggestion of Nature herself. Although man but slowly and painfully follows out the promptings of Nature to their legitimate conclusion, yet Truth, however long concealed, appears clear and beautiful at last.

It was remarked by the ancients that the substance known as amber possessed certain mysterious properties, which we now know are common to glass and many other substances, and which are termed electrical manifestations. They were, consequently, accustomed to say that amber had a soul, and this comprised the sum of their knowledge respecting electricity.

This remarkable affection of matter, which we are accustomed to speak of as a fluid - but which is entirely unaffected by gravitation - in its dual form pervades all bodies, which in their natural state are said to be in a condition of electrical quiescence. If, however, this electrical equilibrium be disturbed by friction or other external causes, the two electrical principles become separated, and their mutual attractive power being no longer satisfied, it becomes an active agent, and the body in question is said to be positively or negatively electrified, as the case may be.

It was not until within the last one hundred and fifty years, that the various facts relating to electricity were observed with sufficient care to afford a basis of generalization, and thus establishing the leading principles of electrical science. About this time the attention of philosophers became directed towards the devising of means of confining this subtle agent, and preventing its escape from conducting bodies. Little by little the scanty stock of knowledge upon the subject was increased by successive experimenters until the year 1816, when RONALDS constructed his Pith-ball Electric Telegraph. From this time forward the progress of the science was more rapid, until the year 1837, when the world-renowned invention of Professor MORSE was brought before the public, and the Electric Telegraph for the first time became a practical realization.

With the practical introduction of the Electric Telegraph in America and England, which took place at nearly the same period (1844), came also the necessity of some effectual means of confining the electric fluid to the suspended line wires, which formed the medium of communication between the apparatus situated in different places. This, though easily accomplished in dry weather, under other circumstances was found to be a problem of almost insurmountable difficulty in the earlier days of the enterprise.




The first insulator used in America consisted merely of cloth, saturated with gum lac, and wound around the wire at the point of contact with the post, and covered with a wooden roof to prevent the access of rain. Then the horn used for lightning rods was tried and abandoned. Then followed the glass insulator, at first in form of an ordinary door-knob. In England, the insulator at first employed was composed of little double cones of earthenware, about the size of an egg, the line wire being threaded through a hole passing longitudinally through the centre, the insulator being secured to the post by means of an iron staple. Every half mile or so ponderous "winders" were attached to a large bolt going through the pole, and only insulated therefrom by a collar of earthenware, giving rise to a leakage of current, which is comparable only to a two inch hole in a three inch water pipe, at intervals of half a mile. The plan of grouping the wires on vertical arms was also admirably adapted to produce "wet contact" or cross connection.

In those days there were no testing instruments other than a rudely constructed galvanometer, and though OHM had published his now celebrated treatise in 1827, his laws lay for many years buried fathoms deep in the pages of scientific memoirs. It is but a few years since the application of resistance measurement was unknown, and the only means of finding an interruption was by trudging along the lire until the cause was perceived, as is the practice among the enlightened Telegraphers of America, even to the present day.

In the year 1846, Mr. GEORGE LITTLE, who had been employed by the original Electric Telegraph Company of England to repair a line of Telegraph on the North Western Railway, which had been badly damaged by lightning, was led to study the difficulties attending the use of the Electric Telegraph, and to provide, if possible, a remedy for such as presented themselves to his observation, and this resulted in the invention of the inverted cup form of insulator, which began to be used extensively during the following year. This was constructed of glass or stoneware, in the form shown in the accompanying cut, by means of which a complete zone of the insulator was protected from falling rain. This was the first step towards the proper method of insulating land lines, which has since become universal all over the civilized and uncivilized world. For this invaluable discovery Mr. LITTLE has not received one cent of compensation from any government in the world. By the use of this invention, it is possible to transmit telegrams in rainy weather to a distance of five hundred miles, which could not otherwise have been transmitted fifty, and sometimes not even five miles.

The actual value of an invention of this kind, in a great commercial country like the United States, for instance, is incalculable. When we think for a moment of the millions of these insulators in use at this moment throughout the world, we may calculate what the modest tax of one mill on each insulator would have amounted to as a yearly income, had the invention been patented. But as it is, all nations freely enjoy the benefits arising from its use.

In common with many of our scientific friends, we can testify to the truly original and practical character of Mr. LITTLE'S discoveries and inventions in the practical application of electricity, prominent among which is his beautiful discovery of electro-specific gravity, made in the year 1850, which is just beginning to attract the attention of Telegraphic Engineers, and will, without doubt, be ultimately adopted as the only practical recording system for long submarine telegraph cables.



Researcher notes: 
Supplemental information: 
Researcher:Bob Stahr
Date completed:September 13, 2005 by: Elton Gish;