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Duncan Stewart (1844-1904) the founder of Duncan Stewart and Co.
1864 Patent in respect of apparatus for calendering, mangling or finishing
1904 Obituary 
DUNCAN STEWART was born at Thornliebank, near Glasgow, on 19th October 1844.
He was educated at Glasgow Academy and at the University, and received his early engineering training in a small engineering works in which his father was a partner, where bleaching and finishing machinery was principally made. As an apprentice he also took a great interest in sugar machinery, and, not content with knowing how the machinery was made, he used to spend much of his spare time in the evenings in the large sugar works at Greenock, mastering the details of the manufacture of the commodity itself, which proved of great use to him at a later time.
On the death of his father in 1864 he left the works, and started the present firm of D. Stewart and Co. (1902), under the name of Duncan Stewart and Co. At that time the firm only employed about a dozen men, but the works were gradually enlarged as the business increased, until from 600 to 800 men were employed.
Soon after starting the works he accepted an offer from a firm who were the owners of a large number of sugar estates in the West Indies, to go out for a limited time as their chief engineer. The experience gained there proved of great value to his business, and he returned to Glasgow with the nucleus of a business in sugar machinery that was destined to make the name of the firm familiar in nearly every sugar-growing country. Large sugar factories have been erected by the firm in Java, Egypt, West Indies, Australia, Mexico, and South America.
He also started to build up a business in bleaching, printing, and finishing machinery, with which he had made himself familiar in his father's works, and a very large number of bleaching and finishing works in the British Isles have some of the firm's machinery at work. As a general engineer he also supplied large rolling-mill engines and hydraulic plant to various steel works, also pumping engines of the largest size at home and abroad, and latterly engines for electric lighting and traction. When the Glasgow Corporation resolved to introduce electric traction for the whole tramway system of the city, he was successful in obtaining a share of the contract for the engines at Pinkston power-station.
One of his most successful inventions was the application of hydraulic pressure to the rolls in sugar mills; another ingenious invention was that of the "continuous centrifugal machine," on which he spent a large amount of thought and much expense, but it was unfortunately not a commercial success. He also brought out several inventions connected with textile machinery.
He always took a great interest in anything relating to the West Indies, and it was with deep concern that he witnessed the decline of the sugar industry in these islands. By strenuous efforts he succeeded in obtaining, in 1898-99, for the West Indies, a British Government loan of £210,000 for the establishment of central sugar factories, through his able statement of the case to the Colonial Secretary.
Unfortunately, he was not destined to reap the fruits of his industry in this direction, as the South African War postponed the scheme, and his illness in 1901-02 removed him from the arena of active business. The scheme has, however, been subsequently adopted almost in its entirety.
In the "eighties" he was invited to become a candidate for the representation of Bridgeton in Parliament, which offer he was, however, obliged to decline owing to business pressure.
His death took place at Eastbourne on 30th October 1904, at the age of sixty.
He became a Member of this Institution in 1818.
1904 Obituary 
THE death took place at Eastbourne on 30th ult. of Mr. Duncan Stewart, of D. Stewart and Co, London Road Ironworks, Glasgow. He was founder of these works some forty years since, and up till two years ago, when his health failed, he was closely associatcd with them, and was one of the best known men in engineering circles in the West of Scotland.
Born near Glasgow about sixty years ago, he received his early training in a small engineering works, in which his father was a partner, where bleaching and finishing machinery was the principal manufacture. As an apprentice he also took a great interest in sugar machinery, and spent much of his spare time in tho large sugar works at Greenock, mastering the details of the manufacture itself, which study afterwards proved of great service to him. On the death of his father in 1864, and when only twenty years of age, be started the firm of Duncan Stewart and Co, the number of employees at first being only about a dozen. As business increased the works were gradually enlarged, until from 600 to 800 men were employed. Soon after starting Mr. Stewart was induced to accept an offer from the firm who were the owners of a large number of sugar estates in the West Indies to go out for a limited time as their chief engineer. The experience gained there and the friendships which he made proved of much value to his business, and he came back to Glasgow having fulfilled his commission to the great satisfaction of his employers with the nucleus of a business in sugar machinery which eventually made the name of his firm familiar in practically every sugar-growing country in the world. Large sugar factories have been erected by the firm in Java, Egypt, West Indies, Australia , Mexico, and South America. Not content with one class of work, Mr. Stewart set himself to build up a business in bleaching, printing and finishing machinery with which he had made himself closely familiar in his father's time; and there are at present probably very few bleaching and finishing works of any importance in the British Isles which have not some of the firm's machinery in them besides others on the continent of Europe, in India and America. In general engineering the firm also have supplied large rolling mill engines and hydraulic plant to steel works in all parts of the kingdom, also pumping engines of the largest size for work at home and abroad. Steam engines up to 2000 indicated horse power or have been supplied to cotton mills in th1s country, in France, and in India. Latterly engines for electric lighting and traction have formed a notable product of the firm's industry. When the Glasgow Corporation resolved on the introduction of electric traction for the whole tramway system of the city, they were successful in obtaining a share of the contract for the engines for Pinkston power station, the larger portion going to an American firm. The relative merits of the machinery were keenly discussed at the time. The home-made engines were installed within the period specified, and it was owing to the promptitude of delivery, and the efficiency of the plant that the tramway system was opened in accordance with the original arrangements.
In connection with the various productions of his firm , Mr. Stewart's ingenuity and skill resulted in many patented features. One of his most successful inventions was the application of hydraulic pressure to the rolls in sugar mills, and what was originally known as Stewart's patent hydraulic attachment is now almost universally applied to mills where a high percentage of extraction is desired. Perhaps his most ingeneous invention was that of the "continuous centrifugal machine," on which be spent a great amount of thought and much money. The difficulties to be overcome, however, proved too great, and the machine, in spite of its ingenuity, was not a commercial success.
Probably because of his early associations, Mr Stewart always took a great interest in West Indian affairs, and it was with deep concern that he witnessed the decline of the sugar industry there. Through his able statement of the case to the then Colonial Secretary, Mr. Chamberlain, he succeeded in obtaining in 1898-9 a British Government loan of £250 000 for the establishment of central sugar factories. Unfortunately, Mr. Stewart was not destined to reap the fruits of his industry in this direction, as the South African war postponed the scheme, and his illness in 1901-2 removed him from the arena of active business in which he had been a strenuous worker for practically forty years. He married in 1879 the daughter of the late Mr. William Beardmore, of Parkhead Forge, and he is survived by her and by two daughters and two sons.