General Sir Charles William Pasley KCB FRS (1780–1861) was a British soldier and military engineer who wrote the defining text on the role of the post-American revolution British Empire: An Essay on the Military Policy and Institutions of the British Empire, published in 1810. This text changed how Britons thought their empire should relate to the rest of the world. He warned that Britain could not keep its Empire by its "splendid isolation". Britain would need to fight to gain its empire, and by using the colonies as a resource for soldiers and sailors it grew by an average of 100,000 square miles (260,000 km2) per year between the Battle of Waterloo and the American Civil War. Serving in the Royal Engineers in the Napoleonic Wars, he was Europe's leading demolitions expert and siege warfare specialist.
Pasley was born at Eskdale Muir, Dumfriesshire, on 8 September 1780. He was highly intelligent, capable of translating the New Testament from Greek at the age of eight. In 1796, he entered the Royal Military Academy at Woolwich; a year later he gained his commission in the Royal Artillery, and he was transferred to the Royal Engineers in 1798.
He was present in the defence of Gata, the Battle of Maida, and the siege of Copenhagen. In 1807, then a captain, he went to the Iberian Peninsula, where his knowledge of the Spanish language led to his employment on the staff of Sir David Baird and Sir John Moore. He took part in the retreat to Corunna and the Walcheren Expedition, and received a severe wound while gallantly leading a storming party at Flushing. During his tedious recovery, he employed himself in learning German.
After discontinuing service, he devoted the rest of his life to the foundation of a complete military engineering science and to the thorough organization and training of the corps of Royal Engineers. Though only a captain, his great success led him to act as the commanding royal engineer at Plymouth for two years and was given a special grant. Because the events of the Peninsular War emphasized the need for a fully trained engineer corps, the war office adopted Pasley's views. He was placed at the head of the new School of Military Engineering at Woolwich in 1812. In 1816 he was elected a Fellow of the Royal Society. 
Palsey developed a new form of pontoon bridge which was adopted in 1817 by the British Army. Each pontoon was split into two halves and you could connect two pointed ends together in cases where you had tidal flow. Each half was enclosed, so reducing the risk of swamping and there were multiple lashing points. The "Pasley Pontoon" lasted until it was replaced in 1836.
Concurrently, Pasley was gazetted brevet major. He became brevet lieutenant-colonel in 1813 and substantive lieutenant-colonel in 1814. The first volume of his Military Instruction appeared in 1814 and contained a course of practical geometry which he had framed for his company at Plymouth. Two other volumes completing the work appeared by 1817 and dealt with the science and practice of fortification, the latter comprising rules for construction. He published a work on Practical Architecture and prepared an important treatise on The Practical Operations of a Siege (1829–1832), which was translated into French (1847).
He became brevet colonel in 1830 and substantive colonel in 1831. From 1831 to 1834, he focused his attention on the standardization of coins, weights and measures, publishing a book on the topic in 1834. In 1838, he was presented with the freedom of the city of London for his services in removing sunken vessels from the bed of the Thames near Gravesend. From 1839 to 1844, he was occupied with clearing away the wrecks of HMS Royal George from Spithead and HMS Edgar from St. Helens. All this work was subsidiary to his great work of creating a comprehensive art of military engineering.
On 23 November 1841, on promotion to the rank of major-general, he was made an inspector-general of railways, replacing Lieutenant-Colonel Sir Frederic Smith. During this period of intense activity on the new railway network, he inspected many new lines, criticising the haste in which some were opened to poor engineering standards. When a cast iron structure collapsed under the weight of a train during the Dee bridge disaster, Pasley came under pressure. He had approved the opening of the Dee Bridge a few months before the tragedy.
In 1846, on vacating this appointment, he was made a K.C.B., and thenceforward was chiefly concerned with the East India Company's military seminary at Addiscombe. He was promoted lieutenant-general in 1851, made colonel commandant of the Royal Engineers in 1853, and general in 1860. He died in London on 19 April 1861. His eldest son, Major-General Charles Pasley (1824–1890), was a distinguished Royal Engineer officer. His daughter Margaret married railway inspector and MP Henry Whatley Tyler.
In 1826, as lecturer in architecture and engineering at the Royal School of Military Engineering at Chatham, he began research and experiments on artificial hydraulic cement, attempting to match or make an improvement over natural or "Roman" cement, invented by James Parker in 1796. In 1830, he succeeded and with chalk and Medway clay, produced a hydraulic lime equal to the natural "Roman" cement and similar to that produced by Joseph Aspdin in Wakefield.
Among Pasley's works, besides the aforementioned, were separate editions of his Practical Geometry Method (1822) and of his Course of Elementary Fortification (1822), both of which formed part of his Military Instruction; Rules for Escalading Fortifications not having Palisaded Covered Ways (1822; new eds. 1845 and 1854); descriptions of a semaphore invented by himself in 1804 (1822 and 1823); A Simple Practical Treatise on Field Fortification (1823); and Exercise of the Newdecked Pontoons invented by Lieutenant-Colonel Pasley (1823).
Links to works
- Essay on the Military Policy and institutions of the British Empire by Charles Pasley (2nd ed., 1811): Part I
- "Fellows details- Charles William Pasley". Royal Society. Retrieved 17 July 2016.
- "UK Military Bridging – Floating Equipment". thinkdefence.co.uk.
- Vetch, R. H.; Sweetman, John (2004), Pasley, Sir Charles William (1780–1861) (Registration required), Oxford Dictionary of National Biography, Oxford University Press, doi:10.1093/ref:odnb/21499, retrieved 13 April 2009
- PR Lewis and C Gagg, Interdisciplinary Science Reviews, 45, 29, (2004).
- PR Lewis, Disaster on the Dee: Robert Stephenson's Nemesis of 1847, Tempus Publishing (2007) ISBN 978-0-7524-4266-2
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Pasley, Sir Charles William". Encyclopædia Britannica. 20 (11th ed.). Cambridge University Press.
- Vetch, Robert Hamilton (1895). "Pasley, Charles (1824-1890)". In Lee, Sidney. Dictionary of National Biography. 43. London: Smith, Elder & Co.
- [ Royal Engineers Museum - Sapper Biographies]