GEORGE FORBES: CARBON BRUSH INVENTOR

Frederick W. Duthie

This article first appeared in the journal of the Institute of Electrical Engineers in April 1996. It appears on this site courtesy of its author. Fred Duthie, a Strathclyde University-educated Aberdonian who researched Forbes’ life during a career with Morganite Incorporated, of Dunn, North Carolina USA. Morganite utilizes Forbes’ carbon brush innovations to this day. During the course of his research, Duthie became so enthusiastic that he styled his own moustache like that worn by his subject so that he could lecture on Forbes’ life in character (he is pictured in this guise below). Today he lives in retirement in the USA. Messages sent to him addressed to this site will be forwarded.

INTRODUCTION

The year of 1985 was particularly significant in that it was the 100th anniversary of two major inventions. In 1885 Gottlieb Daimier and Karl Benz separately produced vehicles driven by gasoline internal combustion engines. In the same year, the first patent on the application of carbon as a current collector for rotating electrical machines was granted to George Forbes.

George Forbes received very little publicity and minimal financial reward for this epoch making innovation. The carbon brush was only one of his many significant contributions to physics and education. Forbes had no interest in commercializing his ideas and unfortunately did nothing to record his life’s work for posterity, preferring instead to preserve the writings and books of his father.

This paper attempts to re-create ‘flesh on the bones’ of George Forbes and review historical developments in brush design and materials.

In researching Forbes, the writer uncovered a great deal of information not previously brought together. For the sake of posterity, the author has written more than originally anticipated regarding Forbes; however, in the manner of Forbes, the author will make no apology in the anniversary year.

GEORGE FORBES

George Forbes was born in Edinburgh, Scotland, April 5, 1849. The lineage of both his distinguished parents was that of ancient Scottish races. He was one of five children of James David Forbes, D.C.L., LL.D, F.R.S., Principal of St. Andrew’s University, who was himself famous for his geological research, particularly his theory on glaciers. His grandfather was Sir William Forbes, a close friend of Sir Walter Scott and Samuel Johnson [1, 2].

George Forbes was educated at Edinburgh Academy (twelve years after Maxwell and Tait), St. Andrew’s and Cambridge Universities[1].

Forbes was elected a member of “The Institution of Electrical Engineers” in 1881, a member of Council from 1891- 1893, and Vice President from 1894-1895 [3].

George Forbes, The Man. What was Forbes like as a person? Judging from the following, he was at least a very colorful individual. Writing about Forbes, William Grimson, Senior Fellow of College, Cambridge, mentions, “Mr. Forbes is a gentleman in mind and manners with abundant energy and l a decided love for his favorite studies” [4].

Professor P.G. Tait writes, “. . . highly conscientious and strong sense of duty. . .”[5]. According to Sam Mavor, “George Forbes, the best type of gentleman, of tall and handsome appearance, splendid physique and athletic bearing, had a singularly attractive personality, fine character, a brilliant intellect and the manners of a courtier. His versatile abilities distinguished him as engineer inventor, astronomer, traveller and philosopher, and the breadth of his knowledge and experience and gift of conversation made him a delightful companion.” [6].

Forbes, however, was probably somewhat unpopular with Americans who read his writing in Blackwood's Magazine: “There are two great mistakes commonly made as to Americans. One is, that they are original inventors; the other is, that they are humorous. Neither of these propositions is true.”

To explain this apparent paradox, he goes on to interpret the difference between designing and inventing: “Invention and humour require a gift of imagination, the same gift that shows itself in poetry and letters, in music, painting, and sculpture; and in no one of these directions has this gift of imagination been found to predominate largely amongst Americans.” He continues to “charm” American readers, “…in that country the manners and customs, as seen by the ordinary traveller, are governed by the average man, who is not a good specimen. He is apt to be the most awful “bounder”, has no taste, and does not know the meaning of the word “repose”; but you need never meet this type except in railway trains and hotels. But the refined American is quite different, and quite like an English gentleman. These are mostly met in Washington and the South. An Englishman in America should always try to retain his Englishness--otherwise in a year or two he will be reduced to the level of an average American. Where all men think themselves equal, individuality is at a premium” (7].

In 1882-1890, we find that Forbes had a residence in Lon- don at 34 Great George Street, Westminster. During this period, he was working with private industry.

In 1906, Forbes built, largely by his own efforts, a home near Pitlochry, in Scotland, to house the books and memorabilia of his father, who died in 1868. Forbes liked to call his house “The Shed,” a large wooden structure which had an observatory on the upper story overlooking Loch Faskally and the hydro-electric scheme which he had first proposed in the early 1900’s. [Editor’s note – the hydro electric scheme was not, in fact started until the 1950s.] It was felt that reference to his home as a shed was to emphasize his relative poverty.

At the age of 61, Forbes boards a tramp steamer, the S.S. Hasland, in Cardiff. While in the Gulf of Lyons, very rough weather is experienced and the ship is foundering when Forbes considers what items he should save. “Tobacco was the first necessity: it supplies the place of food, drink, warmth, dry clothing, and sleep” [8]. Amongst other items saved are a fur coat and a fur rug-these may be the very ones mentioned later in this paper! Exactly why Forbes made the trip to the Mediterranean is not clear.

Dr. John A. Cranston writes that Forbes was “very individualistic and tetchy.” He was a confirmed Tory. In an election in the early twenties, Dr. Cranston asked Forbes whether he had voted. “Voted! Even the Tories are all damn Socialists” [9].

Jean Stockdale, daughter of a past director of the University of Strathclyde, gives her opinion of Forbes in notes entitled “Professor George Forbes as he Appeared to a School- girl.” Forbes, at the time, was in his early seventies. “He appeared to me as a tall, thin, aristocratic old gentleman, who could look straight through you. He used to wear tailored silk shirts with soft collars and loose woven, rather light colored tweeds of ancient vintage. I have a strong suspicion, that if it had not been for the attention of my mother’s darning needle, his needs would have seen the light of day! He liked at least three pairs of blankets on his bed, over which he placed a large fur rug, rather moth eaten and pock marked with tobacco bums as he would smoke in bed. He also wore a long fur coat in similar state, which nearly reached his heels and which my mother would dearly have loved to send to the cleaners! We were to understand that coat and rug had been presented to him by some Russian, I think, aristocrat and were the last word, which neither age, moth nor lighted tobacco could alter. These are a few of my memories of Prof. George Forbes whom we came to look upon as a eccentric, rather pathetic old gentleman, who lived in a fabulous abode called the ‘Shed’ in Pitlochry when not with us” [10]. Forbes was staying with the Stockdales when he delivered his David Elder Lectures on Astronomy [6].

In the late seventies, he was suffering from loss of memory and failing sight. Forbes had to undergo an expensive operation to remove an eye [11].

Forbes, in his later years, went through a period of financial hardship. “He should have made a lot of money in his time, especially in consultancy work. But he was relatively poor” [9]. "George Forbes thought much of his work and little of his reward. When he ceased to read because his eyes grew dim, piety and honour forbade him to sell his father’s books, and he gave them all to St. Andrew's University….These books, some four thousand in number, are of great value….The sale of these books would have brought him comfort, almost wealth, bur money had no place in his thoughts” [1]. In 1928, his friend and colleague, D' Arsy Thompson, successfully petitioned the government, organizations and associates for financial assistance to rescue Forbes from his plight. At this time, Forbes resided at 11 Little College Street in Westminster, London, and was thus able to spend time at his club - the Athenaeum.

In about 1934, Forbes moved to a small hotel at 13, New-parade, Worthing. His health had been deteriorating.

Jean Stockdale would have been interested to know that the fur coat her mother detested had stood the test of time and was still being worn by Forbes. During his time in Worthing, he employed William Earnest Kirby as companion attendant [12].

“Fell in Front of Fire/Burns Accelerate Death” is the column heading of The Worthing Gazette on the inquest of his death on October 22, 1936. The verdict was death by misadventure. The primary cause of death was bronchial catarrh and laryngitis, accelerated by the shock of burning. Forbes had been sitting close to a gas fire when he appears to have slipped off the chair. He was unable to pull himself up, and consequently one leg was burned. He died early next morning. The funeral took place at Durrington Cemetery, the service being conducted by the Vicar of St. Andrew's (the Rev. W, Fowell Swann) [12].

Forbes never married-in fact, there appears to be no reference to an association with anyone of the opposite sex. This is perhaps surprising since it was stated at the inquest that “he always wanted somebody about him as he dreaded being alone” [11].

PROFESSOR GEORGE FORBES SCIENTIFIC ACHIEVEMENTS & EXPLOITS

After graduating, Forbes, at the age of twenty-four, was appointed Professor of Natural Philosophy at Anderson’s University (subsequently known as the Royal Technical College and now as the University of Strathclyde) in Glasgow. During his eight years’ association with Anderson's College, he travelled extensively.

The Transit of Venus. It was in 1874 that Forbes set out to lead a team of scientists in a mail steamer to Valparaiso, thence by HMS Scout to Hawaii. The objective was to spend six months studying the transit of Venus to determine the solar parallax and distance [1,13]. The next transits will be June 8, 2004 and June 6, 2012.

On the morning of Friday, November 20, Forbes and a Mr. Lambert were swimming off Kailua. Lambert got into difficulties when high waves and a strong undercurrent developed. It is recorded that Forbes made noble, but unsuccessful, efforts to save his friend, coming very close to losing his own life in the process [6,14].

Journey through China and Russia. Instead of returning home after his successful observation in Hawaii, Forbes writes, “My work there was finished in six months and I was meditating about my journey home by India or North America when I was told it might be possible to go by Siberia from Peking. I happened at the time to be unhampered by considerations of time and money, and as I should have less chance afterwards of travelling by this route than by the others I determined to try it, and my ignorance of the countries and their languages made me the more anxious to try.” Thus began an adventure that few men would have undertaken. His trip in 1875 by foot, camel, tarantass, and boat, through China, Mongolia, and Russia is on record. From Shanghai, he then travelled to Peking, Changkiakow, Ulan Bator, Kyakhta, Irkutsk, Krasnoyarsk, Tomsk, Perm, Kazan to Moscow and Leningrad and thence to Scotland-a journey of four months and some 5,000 miles.

While in Kyakhta, on the Mongolian/Siberian border, where few foreigners ever set foot, he is introduced to a girl of 17 years from an old Scottish family. Miss Campbell asks Forbes to assist her return to Scotland, to which he agrees. They travel together to Irkutsk (close to Lake Baikal) where they become associated with some exiles from the Polish revolution of 1863. Miss Campbell falls in love with a Josef Szlenker, but the government prohibits the wedding unless she promises never to try to escape from Russia. The promise was given and the ceremony took place in the Roman Catholic Church in Irkutsk. Forbes travels home alone with some misgivings about leaving the couple behind. While in Leningrad, he attempts audience with the Tsar to plead for the release of the couple but is not successful. Having previously met the Duke of Coburg (was the Duke of Edinburgh until he married the only daughter of the Tsar), Forbes wrote to him and was this time successful in obtaining the Szlenkers’ release [15].

‘War news in 1877 – with the Russians’, The preceding is the heading in The Times of February 21,1930. In 1877, George Forbes was in Germany when war broke out between Russia and Turkey. “On the declaration of war my love of adventure determined me to act as war correspondent with one of the two armies for some London newspaper. I hurried home from Germany and wrote to editors direct, as I had no journalistic friends who could use any influence.”

Forbes received an interview with Delane, the great editor of The Times, and eventually is assigned as the only British war correspondent with the Russian army in Asia.

He writes, “I spent one night in Warsaw with the two Siberian exiles whose freedom I had secured a year or two before. They gave me a letter of introduction to a General at the front.” No problems were encountered until the town of Tiflis (now know as Tbilisi) is reached when a delay of nearly six weeks is encountered. The Russians had suspected Forbes of being a spy. In desperation, Forbes contacts Prince Swiatipolk Miski who asks if he is related to Principal James David Forbes. When Forbes reveals that this was his father, the Prince is elated, for he had much admired the father’s contributions to science. Within two days, Forbes receives a letter: “The Prince Swiatipolk Miski has the honour to inform Mr. Forbes that his highness the Grand Duke, General-in-Chief of the army of the Caucasus, has been pleased to grant him permission to the camp of the Russian troops, either before Kars or in the Kobaulete. It is understood that Mr. Forbes must conform himself to the established rules. Tiflis, June 5-17, 1877.”

Forbes actually becomes involved in the conflict. For his leadership and numerous acts of bravery, he is awarded the Russian Order of St. George and several gifts [16].

Velocity of Light. Back home in Scotland, Professor George Forbes resumes with Dr. J. Young, F.R.S., research on the velocity of light based on a modification of Fizeau's method. Their work, concluded in 1880, established a figure of 301,382 km/sec [1]. (Author's note: This is very close to the current figure of 299,792 km/ sec.)

Astronomy. This was one of Forbes' favorite fields, no doubt from the influence of his father. In 1880, Forbes predicted the existence of a trans-Neptunian planet (Pluto) from evidence relating to families of comets attached to planets [17,18].

Electric Traction. During his time at Anderson’s College, Professor Forbes advocated in his lectures the use of electric traction. In 1879, Forbes commissioned to report on how the City and South London Railway should be powered. Forbes recommended electrification. The London Underground (tube) might have been operated by cables had it not been for the suggestions of Prof. Forbes [19,31].

Industry Manager. In 1882, George Forbes joined the private sector for the first time and moved to London. He was appointed manager of the British Electric Light Company, producers of carbon filament and arc lamps. While working with this firm, he made improvements to arc lamps and invented a meter for alternating current measurement. In 1883 and 1884, Forbes was granted patents 3115 and 11244 respectively, on “Dynamo Electric Machines.” In 1884, he exhibited a unit of his own design at the Philadelphia Electrical Exhibition.

It is probable that his involvement with carbon products and dynamo development with this firm led in 1885 to patent #1288, “Improved Means for Establishing Electric Connection between Surfaces in Relative Motion Applicable to the Collectors of Dynamo Machines.” This was the first patent on the use of the carbon brush. G.L. Addenbrooke writes, “He always referred to this work with much modesty, buy there can be no doubt that almost without acknowledgement he presented to the world an idea of great engineering and commercial value, the importance of which he does not seem to have fully grasped at the time” [20].

Harnessing Niagara. “In October 1889, the Niagara Falls Power Company was formed to carry out the great work of utilizing the Niagara Falls on so gigantic a scale that all previous attempts to use water power at once sank into insignificance” [7]. A panel was established of engineers and physicists from the UK, France, Switzerland, and America, with Lord Kelvin as chairman. Forbes was invited to join the panel and, at first, refused. When he considered that all designs tendered would not be satisfactory, he accepted the challenge. Several significant contributions were made by Forbes during the period 1891-1895 when he was consulting electrical engineer on the project. In the design of the generating equipment, he eliminated the need for a flywheel, and thus reduced the stress on the supporting bearings. Locating the rotational part of the equipment on the outside was a total reversal of design practice until that time. The final design was a compromise between his ideas and those of Westinghouse, who built the generating equipment.

Forbes, against most opinions at that time, advocated high voltage alternating current, instead of direct current, for long distance power transmission. His absolute determination that he was right on this and on other matters of policy, despite all obstacles, had a great deal to do with the success of the scheme [7].

Forbes, lecturing in 1893, stated, “All direct current dynamos except the unipolar ones are the combination of an alternator and a commutator, and every advocate of the continuous current that there ever has been, and there are bigoted advocates, would have been convinced in favor of the alternating current dynamo, alternating current and transmission, if you could have told him that you would put a commutator at the far end of the line instead of at the place where you generated your current” [21].

The plant was designed to have a total capacity of 100,000 hp. Each of the alternators supplied 2,250 volts, two phase at 50 Hz. The directly coupled turbines, built by the I. P. Morris Co., rotated at 250 r/min.

Reflecting on the project, Forbes writes, “In conclusion, it is difficult for me to say who were the boldest, the capitalists who embarked on the scheme before any plans were matured, or the manufacturers who moved their factories to this field before a single result had been achieved. The action of both was typically American, but their confidence was not misplaced. Their success is now assured” [22].

The project was not without some controversy. Ferranti alleges that Forbes’ design of alternator incorporated features of a design submitted by C. E. L. Brown. Brown (subsequently formed Brown-Boveri) himself did not make this claim, but was critical of the low generated frequency, that the external rotating field gave poor ventilation and that the armature was too inaccessible [23].

Professor George Forbes felt that he deserved a knighthood for his work on the Niagara project. In December 1894, he wrote to the person he thought would do him most good Lord Playfair [13]. Unfortunately for Forbes, there was to be no recognition in the form for which he had hoped.

Other Hydroelectric Projects. During his term with the Niagara project, Forbes was involved in 1893 in an advisory capacity to the Indian government on the utilization of the power rendered available by the Peryar Irrigation Works in the Madras Presidency [13J.

Forbes supports Sir William Thomson’s proposal to harness tidal energy for conversion to electrical power [24].

Forbes now appears to have earned himself an excellent reputation as a consulting engineer. We find him making surveys with a view to hydroelectric power conversion in South Africa in 1895, at the Huka Falls in New Zealand in 1896, and at the cataracts of the Nile in the years 1897 and 1898. It was Forbes who suggested to Lord Kitchener the use of electric locomotives on the railway that was being constructed across the Nubian Desert from Wadi Halfa to Abu Hamed for the campaign against the Khalifa. At the same time, he was invited to investigate the feasibility of operating the Nile railways by electricity [19,31].

Electricity as a Motive Power. As mentioned elsewhere, Forbes proposed electrically powered trains. One of the main attractions, according to Forbes, was the application of a motor to every wheel of a train. Such an arrangement would allow greater acceleration (particularly important with close proximity stations), greater traction on uphill grades, less wear and tear on tracks, better stability on curves, and would be economically feasible. Of passing interest is Forbes’ comments on the use of batteries to power tram-cars (street cars), boats, or tricycles. “I think that it would be far more economical to use compressed air engines. Ever since 1865, when I examined the compressed air tram-car of Scott Monrieff, which ran so successfully in Glasgow, I have felt sure at this must become eventually the motive power for tramcars, and I have not yet seen any thing to lead me to alter my pinion” [24].

Range Finders. Professor Forbes, in 1901, invented an infantry range finder. During the South African War, Forbes visited South Africa in 1902 to perfect the instrument [6]. Prof. Forbes also devised a formula whereby the range table of a gun can be accurately calculated from that of another gun of a different caliber [20].

Naval Projects. In 1903-1906, Forbes was engaged by the British Admiralty to develop a gunsight range finder for the navy [1].

“During World War I, he invented a method of signalling between submarines utilizing the principle of converging bearns of light. The admiralty also placed a cruiser at his disposal to enable him to carry out trials on the scraping of barnacles from the bottom of ships to save the necessity of coming into dry dock. He subsequently applied to patent this and und to his annoyance that a patent already existed which had been taken out by the captain of the naval cruiser” [9].

CARBON DEVELOPMENTS

Early Current Collectors. Michael Faraday in 1832 used copper rods wetted with mercury for the conveyance of current to a rotating disc. Mercury alone in the form of “pools” was used by several inventors including Forbes. Laminated copper or brass foil was also frequently employed. In 1870 ZT. Gramme employed collectors comprised of a bunch of wires, which, when worn, took on the appearance of a shaving brush. In 1884, O. Schulze patented metal gauze brushes, All of the above suffered from a major disadvantage: excess wear of the current collecting components. Various lubricants, including graphite, were employed. It is understood I that some of the collectors made from laminating copper were coated with lampblack, possibly by holding them over a burning candle.

The First Carbon Brushes. The original carbon brushes did not look at all like those we are familiar with today. The. actual brushes employed by Forbes had, until recently, been stored in a handmade soldered tin container, with pull-off lid. On the outside of the box was affixed a label, the wording on which had badly faded. By means of ultraviolet light, the cursive script read, “The first Carbon brushes/used for dynamo electric/services. These ones supplied to the Forbes/…….er dynamo.” The dots indicate indecipherable letters [25]. It is possible that the missing word is “homo polar.”

A detailed examination of the brushes has been conducted by Morganite researchers [26]. The actual collector, made from retort carbon, was comparatively thin. According to Patent #1288, it was Forbes’ intention that the carbon portion be as thin as possible to reduce the resistance of the contact, while strengthening the “plates” by attaching them to a copper backing. The carbon was copper plated and soldered to the metal backing. Initially, the carbon was produced from battery plates or arc lighting electrodes. In the case of non- polar dynamos, Forbes engaged the copper backing in slots in the stator and applied spring pressure to the center at a reaction angle to the direction of rotation of the disc. The purpose of the blind hole in the backing is not absolutely clear. In one brush, there remained traces of what may have been braided copper conductors. It is concluded that the holes may have had alternative functions: to align the spring or to provide a well into which a connection was soldered.

Commercialization of the Carbon Brush. Forbes tried to interest a British firm to employ the brush in their electrical machines. After three months of experimenting, the company “acknowledged their great merit, but never thought of trying to introduce them for general use….“ [27]

Forbes sold his American rights to the patent for a mere £2,000 (at that time equal to $8,000) to Westinghouse [27]. Forbes no longer appears to be associated with the carbon brush, either in product development or commercialization. No mention has been found of any royalties being paid by any UK manufacturers.

The First Application of the Carbon Brush. The first commercial application of the carbon brush occurred in 1888. The story is best told by Elihu Thomson: “It is, I think, true that no single thing has had a greater or more direct influence, upon the technical success of railway machinery than the introduction of the carbon brush as a substitute for the various forms of metal brush, many forms of which had been tried previously on railway motor commutators but without even the beginning of success. Simple as this substitution was, the results are of the greatest importance. The pioneers in electric railway work had been struggling with the many problems presented, not the least of which was to get a motor Commutator to run under varying loads without spark, to run in either direction without trouble, and without need of changing the lead, and above all to endure for a reasonable time.

“All forms of metal brush had been tried and become acknowledged failures. They were only calculated, under the harsh conditions, to be ground and to grind the commutator, into dust at a rapid rate (such dust being scattered by the pound along the line of way), with the production, at the same time, of a flickering greenish illumination under the car, an illumination all the more ghastly on account of the havoc known to be going on and of which it was an unfailing index. It is not too much to say that before the carbon brush was substituted there was in prospect inevitable failure; disaster not unforeseen, but all to evident.

“But how did it come about? I do not know that the circumstances have ever been detailed in print, and it shall be my present purpose to fill this gap in the history of electric railways and, at the same time, to pay tribute to the memory of Mr. Chas. J. Van Depoele, truly a pioneer in this art and to whom was due the suggestion of the use of carbon as a brush for railway motors.

“It came about in this way. We had been trying to use on the first roads installed by the Thomson-Houston Co. (Author’s note: now GE) in 1888, various forms of copper and other metal brushes, all of which, however, had soon been condemned as either quite worthless for the purpose of so nearly worthless as practically to be so. A discussion of the matter between Mr. Van Depoele and myself, attended as it was by many expressions of misgivings as to the fate of the electric railway work unless a radical change for the better could soon be made in the commutators, led him to remark in substance: “I have used a plate of carbon as a brush on a stationary motor which carbon brush worked well, and I think it might answer the purpose here.”

“The trial was made and was at once so eminently successful that scarcely any time elapsed before the metal brush became a thing of the past, not only on the Thomson-Houston railway motor apparatus, but on others also as soon as the news got abroad. We called the new brushes “carbon brushes,” though of course they have very little of the brush proper about them.

“I remember inspecting one of the first carbon brushes applied in railway work to a motor commutator after it had had a reputed run of 5,000 miles. It had only worn down to a moderate extent and the commutator retained its smooth black polish. Then it was that we knew that the difficulty, at one time so serious and exasperating, had been removed and our reputations as skilful electrical engineers saved for the time.”

Thomson continues: “The first proposal to use carbon as a current collecting brush for dynamos was made by Prof. George Forbes, in a British patent of 1883” [28]. (Author's note: The year was in fact 1885.)

The preceding article, written six years after the fact, mentions that Van Depoele had previously tried carbon for a brush with successful results. Thomson does not appear to challenge the originating source of the carbon brush, nor explains why Van Depoele delayed suggesting that carbon be tried!

According to Holm [29], A. L. Rohrer, an engineer with the Thomson-Houston Co., had made written notices to the effect that between 1881 and 1885 Van Depoele had unsuccessfully experimented with carbon as a brush material. This reference contradicts Thomson!

To add further to the controversy, another reference states: “The patent itself did not seem to possess much value, for we soon find the carbon brush being used freely by others, notably by Sprague in 1887 for his railway motors for the Richmond trolley installation” [30]. If this information was correct, it would give Sprague, not Van Depoele, credit for the first practical application of the carbon brush! Sprague was responsible for the very first complete system of electric street car, operating in Richmond, VA, in 1878 [31].

While Forbes can unquestionably claim the first carbon brush patent, the credit for successfully implementing the idea is with Van Depoele or Sprague. All were great men, and who was first is not really that important.

As E. W. Rice, Jr., President of G.E. Co., stated in his address to the Society of Electrical Engineers in 1914, “I sometimes wonder whether the present generation of electrical engineers have any conception of the wonderful revolution which was produced in the electrical industry both in design and operation of electrical machinery, by the advent of the carbon brush. I have no hesitation in saying that, in my judgment, it was the most wonderful and valuable advance that was ever made in the art with relation to commutating machines. There is no other single element of design that compares with it in importance….” [32].

ACKNOWLEDGEMENTS

The author wishes to express appreciation to the following who have helped immensely in the preparation of this paper: My wife, Ann, without whose support this paper would not have been written. Tony Ford, Albert White and Rob Taylor of Morganite Electrical Carbon Ltd., UK. Peter Mitchell, Nobrac Carbon Ltd.; UK. My colleagues at Morganite Incorporated. Charles G. Wood, MA, M.Litt, FLA, of Doune, Scotland, formerly University Librarian, the University of Strathclyde. James S. McGrath, MA, DAA, University of Strathclyde, Glasgow, Scotland. Dr. George Wise, General Electric Co. Charles Ruch, Westinghouse Electric Corp.

REFERENCES

1. Obituary Notices of Fellows of the Royal Society, Vol. 2, pp. 283-286: Jan. 1958.

2. Dictionary of National Biography, Vol. 19: 1889

3. The Institution of Electrical Engineers, letter to Albert E.S. White: Jun 5,1985.

4. Testimonial by William Grimson in G. Forbes’ papers at St. Andrew’s University: Aug./Sept. 1872.

5. Testimonial by Prof. P.G. Tait in G. Forbes’ papers at St. Andrew's University: Aug./Sept. 1872.

6. Sam Mavor, Memories of People and Places, University of Strathclyde, M201/18, pp. 61-68.

7. G. Forbes, “Harnessing Niagara,” Blackwood's Magazine, Sept. 1895

8. George Forbes, F.R.S., “Shipwrecked,” Blackwood's Magazine, pp. 322-343, Sept. 1895.

9. Conversation with Dr. John A. Cranston, University of Strathclyde: June 15, 1967.

10. Jean Stockdale, “Professor George Forbes as He Appeared to a School-girl,” University of Strathclyde, Feb. 1968.

11. Trotter correspondence, MSS 19709-19734, St. Andrew's University. 12. Worthing Gazette, Oct. 28, 1936.

13. G. Forbes' letter to Lord Playfair, KCB, Dec. 3, 1894.

14. “Transit of Venus Expedition,” Extract of Mr. Forbes' Journal, Nov. 20, 1874.

15. Forbes’ handwritten notes, Box XI No. 12, St. Andrew’s University. 16. The Times, London, Feb. 21 and 22, 1930.

17. Arthur V. Howard, Dictionary of Scientists, London, Chambers, 1958.

18. Dr. John A. Cranston letter to G. F. of Mar. 1, 1968, M201/17, University of Strathclyde.

19. The Times, London, Oct. 24, 1936.

20. “Obituary Notices,” Proceedings Philosophical Society, #49, pp. 698-700, 1937.

21. International Electrical Congress, Chicago, p. 451: Aug. 21-25, 1893 22. James E. Brittain, “Turning Points in American Electrical History,” IEEE Press, pp. 126-130.

23. James E. Brittain, “Turning Points in American Electrical History,” IEEE Press, pp. 129-130.

24. Prof. George Forbes, “Electricity as a Motive Power,” Van Nostrand's Engineering Magazine, #29, pp. 161-172: 1883.

25. Charles G. Wood, MA, M. Litt, FLA, letter to F. W. Duthie of April 3, 1985.

26. A.E.S. White inter-company letter to F. W. Duthie of May 31,1985. 27. Forbes' letter to Prof. D'Arcy W. Thompson, MSS 19709-19734, St. Andrew's University.

28. Elihu Thomson, “How the Carbon Brush Came into Use,” The Electrical Engineer, #335: Oct. 3, 1894.

29. Ragnar Holm, Electrical Contacts Handbook, pp. 398-401: 1958. 30. The Journal of the Franklin Institute, Oct. 1926.

31. G. Forbes, "Application of Electric Power in Trunk-line Railways," The Engineering Magazine, pp. 1-11, Oct. 1897.

32. E. W. Rice, Jr., "The Beginning of the Carbon Brush," Extract from address at MIT: April 29, 1914.

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