He then studied at Bowdoin College, Brunswick, Maine and while living in Brunswick he met Elizabeth F Perry who he later married; they had three children. He graduated from Bowdoin College with a B.S. in 1875, following which he undertook postgraduate studies for his Master's Degree in the John C Green Scientific School at Princeton. This three-story building, devoted entirely to science classrooms and laboratories, was being built in 1873. Upton became the very first student to officially earn, by examination, a graduate degree from Princeton. He received the degree of Master of Science from Princeton in 1877 after being instructed by Cyrus Fogg Brackett. It was Brackett who, in 1889, founded at Princeton the first school of electrical engineering in the United States. After graduating from Princeton, he went to Berlin where he studied under Hermann von Helmholtz during the academic year 1877-78. While in Berlin he attended Helmholtz's lectures on mathematical ways to analyze electrodynamics.
Thomas Edison had set up a laboratory in Menlo Park, New Jersey, in 1876. He asked Helmholtz for advice on someone with good theoretical skills who might work for him as his assistant. Helmholtz recommended Upton, as did Grosvenor P Lowrey, but Upton's mother was not happy that her son was going to undertake such work, expecting him to go into the academic world :-
Upton ... promised his mother that working for Edison would help him "learn how to earn money." "Everyone must work and it is not always the most agreeable thing in the world," he confessed to her.However, his character meant that he did not find it easy adjusting to the demands of his position :-
Edison hired Upton with the oblique promise that perhaps at some future date he might be assigned to take charge of a telephone system in another city. It was a struggle for the diligent, admittedly absentminded Francis, engaged to be married to his beloved Lizzie, and dreaming of a sedentary existence, to enter the world of commerce so quickly and on such an unexpectedly heady level, especially as he had hoped to return to Germany and "the quiet life." But within the year, this self-effacing and loyal soldier ... professing absolute faith in Edison's ability to achieve ultimate success, affectionately nicknamed "Culture" by his boss because of his introspective, learned mien, piano-playing talent, and impeccable educational credentials, had obtained a 5 per cent interest in all profits accrued from the electric light, a lucrative deal, considering the value of the stock offered by the Edison Electric Light Company eventually soared from $100 to $3,500 a share.Upton worked with Thomas Edison on mathematical problems associated with devices such as the incandescent lamp, the watt-hour meter and large dynamos. Although Edison was a genius as an inventor he had no formal education so was unable to translate his intuition into mathematics. For this he relied on Upton who produced mathematical formulations of Edison's ideas :-
Edison liked and respected Upton, for the latter had acquired a brilliantly profound store of knowledge. And under Edison's guidance he soon gained the necessary experience to make theory and practice meet. It was always edifying to listen to their arguments, and often a group of us would gather round and drink in every word that was spoken. Reasoning and sparrings between Edison and Upton often led to new experiments ...Upton went to Menlo Park, New Jersey, the laboratory that Edison had set up. The laboratory was a remarkable research environment for Upton to undertake his research in. Better equipped than most of the leading university laboratories, it possessed the finest equipment available. Galvanometers, storage batteries, induction coils, wire chemicals, photographic equipment and a forge were available. It also had a research library where scientific publications were held. About twenty skilled machinists, in addition to the mathematical physicist Upton, staffed what was the first ever industrial research laboratory.
In 1879 the design of the electric light bulb was perfected. Despite several eminent scientists predicting that electric light bulbs in a circuit would never work, a lamp powered by current produced by dynamos was demonstrated on 21 October 1879. It was Upton's home in Menlo Park which was the first private house in the world to be lit by electricity, the lamps being powered by a station in Menlo Park capable of lighting 30 bulbs. Upton became a partner and the general manager of the Edison Lamp Works which was established in 1880. This became part of the General Electric Company in 1892.
In  Francis Jehl, an assistant of Edison's at Menlo Park, describes Upton while he was working there during 1878-80:-
Francis Robbins Upton ... came to Edison at Menlo Park ... in November 1878. He was recommended by Grosvenor P Lowrey, a New Englander, who knew the Upton family that was connected with the philanthropist Peabody. Upton was a scholar and a gentlemen, brought up in a good New England fashion by a well-to-do family. He was educated both in this country and abroad, an possessed a mild, modest disposition combined with keen intelligence. His versatile knowledge of physics made him a most valuable assistant to Edison at that period.There is an often-told anecdote relating to Upton calculating the volume of a flask. Many versions are rather inaccurate while that by Jehl seems entirely authentic :-
While a bachelor, he was a star boarder at the Jordan house. In September, 1879, he took a vacation and went to Brunswick, Maine, to marry his college sweetheart, Miss Elizabeth F Perry. She was said to be the fairest damsel of the little college town. If I recall correctly, Charles L Clarke was present at the wedding ceremony, for he and Upton were once fellow students and chums.
I still remember when Upton brought his bride to Menlo Park. She was a fine, delicate young lady, well educated and of a kind, pleasant personality. Occasionally the Uptons had visitors from New England, among them Upton's sister Miss Sadie Upton. I recall her well. She was a smart, attractive young lady with a distinguished swing, and when she came once or twice to the laboratory, the boys all forgot their experimenting.
The Uptons occupied a fine old residence opposite the stairs leading down to the railroad station, and facing the old Post Road to Philadelphia. The homestead still stands; it has been kept ever since in such good order that it shows none of the ravages of time. In the summer of 1880, Upton took his young wife home to her parents in Brunswick, Maine. There their first child was born on August 24, 1880, and named for its mother, Elizabeth Fenno Upton.
While at Meno Park, Mrs Upton often attended Mrs Edison's informal parties, since she was a sociable and agreeable person whose pleasant demureness made friends everywhere. Mrs Edison frequently visited the Upton home; it seemed to me that these two were more friends than 'just neighbors'.
I was once with Mr Upton calculating some tables he had put me on, when Mr Edison appeared with a glass bulb having a pear-shaped appearance in his hand. It was the kind we were going to use for our lamp experiments; and Mr Edison asked Mr Upton to please calculate its cubical content in centimetres. Now Mr Upton was a very able mathematician, who after he finished his studies at Princeton went to Germany and got his final gloss under the great master Helmholtz. Whatever he did and worked on was executed in a purely mathematical manner and any Wrangler at Cambridge would have been delighted to see him juggle with integral and differential equations with a dexterity that was surprising. He drew the shape of the bulb exactly on paper, and got the equation of its lines with which he was going to calculate its contents, when Mr Edison again appeared and asked him what it was. He showed Mr Edison the work he had already done on the subject and told him he would very soon finish calculating it. "Why," said Edison, "I would simply take that bulb and fill it with mercury and weigh it; and from the weight of the mercury and its specific gravity, I'll get it in five minutes, and use a lot less mental energy than is necessary in such a fatiguing operation.We noted that Upton became general manager of the Edison Lamp Company, first in 1880 at Menlo Park, then later in Harrison, New Jersey. Edison had set up various electric light companies in Europe but by 1884 these were in some financial difficulties. Upton went to inspect these European factories and while he was there he saw a transformer which was being used to deliver alternating currents. He advised Edison of the potential for such a system and advised him to purchase the American rights. This Edison did but later, as he did not believe in alternating currents, allowed his option to lapse. Of course, Upton was quite correct in his assessment and alternating currents were to become the norm. This is certainly a case where Upton's deep scientific understanding showed itself superior to Edison's intuitive approach. After the death of his first wife, Upton married Margaret in 1889. In August of that year the newly married Francis and Margaret Upton, along with Thomas and Mina Edison, were present at the Paris Universal Exposition. They attended various dinners and performances, as well as making visits to the Eiffel Tower, Versailles, and other attractions
In 1894 Upton left the Edison Lamp Company which he had managed up to that time, but four years later he was back being employed by Edison, now as an efficiency engineer at the New Jersey & Pennsylvania Concentrating Works. Ore milling produced sand as a by-product which Upton very successfully sold to cement manufacturers. Edison saw the chance to make money and entered the cement business and, when Upton's ore milling business collapsed, he went to work for Edison's Portland Cement Company. He left the business in 1911 but retained his own business interests selling bricks and sand.
One of the honours bestowed on Upton was the presidency of the Edison Pioneers. This select group of twenty-eight men was set up to honour those who had been most prominent in the electrical field. On 11 February 1918, Edison's seventy-first birthday, the Edison Pioneers met for the first time. Upton is also honoured by Princeton University, which now has the Francis Robbins Upton Fellowships named in his memory.
Article by: J J O'Connor and E F Robertson