See N. C. Wilson, Treasure Express: Epic Days of the Wells Fargo (1936); L. Beebe and C. Clegg, U.S. West: The Saga of Wells Fargo (1949).
Armstrong was educated at private schools in Newcastle (The Royal Grammar School) and Whickham, near Gateshead until he was sixteen, at which point he was sent to Bishop Auckland Grammar School. Whilst there, he often visited the nearby engineering works of William Ramshaw. During his visits he met his future wife, Ramshaw’s daughter Margaret, six years his senior.
Armstrong’s father was set on him following a career in the law, and so, after grammar school, he became articled to Armorer Donkin, a solicitor friend of his father’s. He spent five years in London completing his legal education and returned to Newcastle in 1833. In 1835 he became a partner in Donkin’s business and the firm became Donkin, Stable and Armstrong. Armstrong now felt settled in his career and so, he proposed to Margaret Ramshaw. She accepted and they were soon married, going to live in Jesmond, a suburb of Newcastle. Armstrong worked for eleven years as a solicitor, but during his spare time he showed a considerable interest in engineering.
In 1845 a scheme was set in motion to provide piped water from distant reservoirs to the households of Newcastle. Armstrong was involved in this scheme and he proposed to Newcastle Corporation that the excess water pressure in the lower part of town could be used to power a Quayside crane specially adapted by himself. He claimed that his hydraulic crane could unload ships faster and more cheaply than conventional cranes. The Corporation agreed to his suggestion, and the experiment proved so successful that three more hydraulic cranes were installed on the Quayside.
The success of his hydraulic crane led Armstrong to consider setting up a business to manufacture cranes and other hydraulic equipment. He therefore resigned from his legal practice. Donkin, his legal colleague, backed him in his career move and provided financial backing for the new venture. In 1847 the firm of W.G. Armstrong & Company bought 5½ acres of land alongside the river at Elswick, near Newcastle, and began to build a factory there. The new company received orders for hydraulic cranes from Edinburgh and Northern Railways and from Liverpool Docks, as well as for hydraulic machinery for dock gates in Grimsby. The company soon began to expand. In 1850 the company produced 45 cranes and two years later, 75. It averaged 100 cranes per year for the rest of the century. In 1850 over 300 men were employed at the works, but by 1863 this had risen to 3,800. The company soon branched out into bridge building, one of the first orders being for the Inverness Bridge, completed in 1855.
However, just when it looked as if the new gun was about to become a great success, a great deal of opposition to the gun arose, both inside the army and from rival arms manufacturers, particularly Joseph Whitworth of Manchester. Stories were publicised that the new gun was too difficult to use, that it was too expensive, that it was dangerous to use, that it frequently needed repair and so on. All of this smacked of a concerted campaign against Armstrong. Armstrong was able to refute all of these claims in front of various government committees, but he found the constant criticism very wearying and depressing. In 1862 the government decided to stop ordering the new gun and return to muzzle loaders. Also, because of a drop in demand, future orders for guns would be supplied from Woolwich, leaving Elswick without new business. Compensation was eventually agreed with the government for the loss of business to the company. Unfortunately, the government would not release the company from its agreement not to sell armaments abroad, so that avenue was closed to it. Eventually, the restriction was relaxed, and the company was able to sell guns to both sides in the American Civil War.
In 1876, because the 18th century bridge at Newcastle restricted access by ships to the Elswick works, Armstrong’s company paid for a new Swing Bridge to be built, so that warships could have their guns fitted at Elswick. In 1882 Armstrong’s company merged with Mitchells to form Sir William Armstrong, Mitchell and Co. Ltd. and in 1884 a shipyard opened at Elswick to specialise in warship production. The first vessels produced were the torpedo cruisers “Panther” and “Leopard” for Austria-Hungary. The first battleship produced at Elswick was H.M.S Victoria, launched in 1887. The ship was originally to be named Renown, but the name was changed in honour of the Queen's Golden Jubilee. Armstrong drove the first and last rivets. The ship was ill-fated, as she was involved in a collision with H.M.S. Camperdown in 1893 and sank with the loss of 358 men, including Vice-Admiral Sir George Tryon. An important customer of the Elswick yard was Japan, which took several cruisers, some of which defeated the Russian fleet at the Battle of Tsushima in 1905. It was claimed that every Japanese gun used in the battle was provided by Elswick. Elswick was the only factory in the world that could build a battleship and arm it completely.
The Elswick works continued to prosper, and by 1870 it stretched for three-quarters of a mile along the riverside. The population of Elswick, which was 3,539 in 1851, had increased by 1871 to 27,800. In 1894, Elswick built and installed the steam-driven pumping engines, hydraulic accumulators and hydraulic pumping engines to operate London’s Tower Bridge. In 1897 the company merged with the company of Armstrong’s old rival, Joseph Whitworth, and became Sir W.G. Armstrong, Whitworth & Co Ltd. Whitworth was by this time dead.
Armstrong gathered many excellent engineers at Elswick. Notable among them were Andrew Noble and George Wightwick Rendel, whose design of gun-mountings and hydraulic control of gun-turrets were adopted worldwide. Rendel introduced the cruiser as a naval vessel. There was great rivalry and dislike between Noble and Rendel, which came into the open after Armstrong’s death.
He had often visited Rothbury as a child, when he was afflicted by a severe cough, and he had fond memories of the area. In 1863 he bought some land in a steep-sided, narrow valley where the Debdon Burn flows towards the River Coquet near Rothbury. He had the land cleared and supervised the building of a house perched on a ledge of rock, overlooking the burn. He also supervised a programme of planting trees and mosses so as to cover the rocky hillside with vegetation. His new house was called Cragside, and over the years Armstrong added to the Cragside estate. Eventually the estate was and had seven million trees planted, together with five artificial lakes and 31 miles of carriage drives. The lakes were used to generate hydro-electricity, and the house was the first in the world to be lit by hydro-electricity, using incandescent lamps provided by the inventor Joseph Swan.
As Armstrong spent less and less time at the Elswick works, he spent more and more time at Cragside, and it became his main home. In 1869 he commissioned the celebrated architect Richard Norman Shaw to enlarge and improve the house, and this was done over a period of 15 years. In 1883 Armstrong gave Jesmond Dene, together with its banqueting hall to the city of Newcastle. He retained his house next to the Dene. Armstrong entertained several eminent guests at Cragside, including the Shah of Persia, the King of Siam, the prime minister of China and the Prince and Princess of Wales.
Armstrong advocated the use of renewable energy. Stating that coal "was used wastefully and extravagantly in all it's applications", he predicted in 1863 that England would cease to produce coal within two centuries. As well as advocating the use of hydroelectricity, he also supported solar power, stating that the solar energy received by one acre in tropical areas would "exert the amazing power of 4000 horses acting for nearly nine hours every day"
The University of Newcastle was originally founded by Lord Armstrong in 1871 as the College of Physical Science, later Armstrong College in 1904. He was twice president of the Institution of Mechanical Engineers.
Armstrong gave £11,500 towards the building of Newcastle’s Hancock Natural History Museum, which was completed in 1882. This was an enormous sum in those days.
Lord Armstrong's generosity extended beyond his death. In 1901 his heir gave £100,000 for the building of the new Royal Victoria Infirmary in Newcastle upon Tyne. Its original 1753 building at Forth Banks near the river Tyne were inadequate and impossible to expand.