Arthur Woolf (1766-1837) was an English engineer who made major contributions to the design and construction of steam engines.
1766 November 4th. Baptized at Camborne in Cornwall, the eldest son of Arthur Woolf Sr. and his wife, Jane Newton. Arthur Woolf Sr. was a 'bal carpenter' (a millwright) at Dolcoath Mine
He was apprenticed to a carpenter at Pool, near Camborne, and after the expiry of his indentures he went to London.
Woolf left Cornwall in 1785 to work for Joseph Bramah's engineering works in London. He worked there and at other firms as an engineer and engine builder, when he returned to Cornwall. Michael Loam, inventor of the Man engine, was trained by him.
1800 Invented an apparatus for heating water using waste steam, with means of controlling the temperature, installed at Meux Brewery.
1800 Employed by Richard Trevithick.
1803 in Trevithick's pay, sent to London with the first high-pressure engine.
c1803 He was working for the Meux's Brewery in London as Resident Engineer.
1803 Woolf obtained a patent on an improved boiler for producing high pressure steam.
1805 he patented his best-known invention, a compound steam engine. Woolf had appreciated the fact that instead of exhausting the steam from a high presssure engine, it could be passed to a low pressure condensing engine to extract more energy, hence the compound engine. Compound engines became popular on the Continent, due to the relatively high cost of coal. In France the compound engine became known as the machine de Woolf.
Woolf's first compound engine was installed at Meux's Brewery, with the main parts made by Fenton, Murray and Wood. Performance was disappointing, partly due to roughness of the low pressure cylinder bore causing problems with piston sealing, and partly due to a mismatch between the sizes of the high and low pressure cylinders. Improvements were slowly implemented, including fitting a larger HP cylinder and reboring the LP. The engine was tested in March 1808 by Richard Trevithick, witnessed by Davies Gilbert, who found the engine to be very economical, but restricted in output by the size of the boiler.
John Rennie declared that the engine's performance was inferior to those of Boulton and Watt, and as a result the brewery bought a 30 HP engine from B&W and discarded Woolf's engine, leading to Woolf's resignation. However, in 1811, two men who superintended Meux's engines signed a sworn affidavit stating the Boulton & Watt engine used more fuel than Woolf's to do the same work, and that the increased consumption of coal cost the brewery above £1000 per annum.
Entered in to a parnership with Humphrey Edwards, a millwright of Mill Street, Lambeth, for producing engines and boilers; this agreement was dissolved in 1822.
Woolf paid great attention to the accuracy of machining of engine components, and designed and produced machinery, including self-acting lathes, to improve accuracy and quality of finish and to reduce production costs. He was dissatisfied with hemp piston packing, and developed metallic piston rings, originally prpoposed by Rev. Dr, Cartwright.
1811 Advertisement: 'WOOLF’S PATENT STEAM ENGINE. London, April 17,1811. THIS is to certify, that we, the undersigned, were present on the 14th of March, 1811, on the premises of John Hodgson, Esq. and Co. to witness an experiment made with Steam Engine of eight horses' power, erected by Messrs. Bolton and Watt, to ascertain what quantity of wheat could be ground by the said Engine with a given quantity of coals. The Engine was in good working condition, the mill-stone in good order, and the experiment was made with one pair of stones, French burrs, 4 feet 2 inches diameter.
The Engine was worked with proper care and attention for three hours and fiity minutes, and in that time ground three quarters, seven bushels and a half of wheat, Winchester measure, with five and one third of a bushel of coals. The weight of the wheat was 59 pounds, neat, per bushel. The coals were from Collingwood Main, 448 pounds.
James Burton Engineer, Richard Dewdney, Miller, John Penn, Engineer, George Nicholls, Miller at Messrs. Hodgsons, Richard Pearce, Miller, Messrs. Hodgsons.
London, 17th April, 1811.
The advert continued with the results of other witnessed tests at Woolf and Edwards, Mill Street, Lambeth, and then concludes: From the above Certificate it appears, that with one of Messrs. Bolton and Watt's best Engines of eight horses’ power, not quite six bushels of wheat, Winchester measure, can be ground into flour with one bushel of 84 pounds of Newcastle coals; and that with the same qiantity of coals, Woolf's nine horse Engine can grind from 20 to 24 bushels of the same wheat. In other words, Woolf's Patent Steam Engine of nine horses' power can lift from 40 to 45 millions of pounds one foot high, with one bushel of coals.—Engines of greater power can lift considerably more with the same quantity of fuel.
For Licences to Construct or use Woolfs Steam Engine apply to Mr A. Woolf, Camborn, Cornwall: or Mr. Alexander Tilloch, Star Office, Temple-bar.
N. B. Engines on Mr. Watt’s principle may altered to embrace Woolf's improvements, at moderate ex-pence.
*The Mill and Patent Steam Engine are to be Sold by Private Contract.— Apply on the Premises, Mill-street, Lambeth. 
1813-14 Erected steam stamps for crushing ore at Wheal Fanny, Redruth.
1816 Became superintendent of Hayle Foundry in overall charge of the foundry from March 1816 onwards.
1824 he erected engines at Wheal Busy.
From 1818 until May 1830 he was engineer at Consolidated Mines, and he was at various times consulting engineer to at least thirty Cornish mines. In 1827 he erected engines at Consolidated Mines.
He also introduced improvements to Richard Trevithick's boiler design. His engines were, however, quickly superseded by Trevithick's high-pressure single-cylinder engine, which had the advantage of greater simplicity in construction.
From about 1816 until 1833 he acted as superintendent of Harveys of Hayle engine foundry.
He was also active as a civil engineer, and a notable construction was the swing-bridge he designed for the Penryn to Falmouth road.
Woolf's first wife died in 1830, aged sixty-seven, and on 15 June 1832 he married Emblin Vincent.
1830 Arthur Woolf of Camborne, Civil Engineer, became a member of the Institution of Civil Engineers.
1837 October 26th. Arthur Woolf died at the Strand, Guernsey
Woolf developed a type of boiler designed to work at relatively high pressures. The arrangement can be seen in the first three illustrations above. There were two tubes exposed to the full heat of the fire, and above these was the boiler drum, part of whose bottom surface was heated by the gases which had passed over the tubes. The gases were then directed over more of the surface of the drum (below the waist line), before escaping up the flue. The overall impression is of a design much more modern than 1819, but this impression is undermined by the fact that it was made of cast iron. As T. R. Harris noted, only small wrought iron plates were available at the time, requiring numerous riveted joints, while the art of the ironfounder 'was far in advance of the boiler-plate maker'.
Note the manhole cover, which is pressed against its seat by internal steam pressure. The cover and branch are oval, allowing the cover to be inserted from outside. The feed water supply pipes have two-bolt flanges, presumably screwed onto the pipe. A similar principle was later adopted on high pressure hydraulic systems. At the left hand end of the drum is a cast iron mounting which contained two weighted safety valves and a float. The float is missing on the model, and its purpose is uncertain. It appears not to be connected with the feed water supply, and it may have acted to release steam to warn the operator of low water level.
T. R. Harris wrote a biography, published in 1966, aimed at bringing Woolf's achievements out of obscurity.. This provides the source for much of the technical information presented above.
The Council have to regret the loss to the Institution by death of its Member, Arthur Woolf.
This distinguished individual was born at Camborne, in Cornwall.
He was a millwright, and in that capacity went to London, and was employed in Meux's Brewery.
In 1804, he took out a patent for his Two Cylinder Engine, working high pressure steam in a small cylinder, and allowing it to expand in a large one.
When he first commenced erecting engines in Cornwall, he induced the proprietors of the Foundries to improve their machinery, that a better style of workmanship might be used in the manufacture of steam engines; and he introduced an improved Hornblower’s double beat valve.
The work done at the Consolidated Mines, proves him to have been a person of great talents.
In October, 1814, the average duty of the engines in Cornwall was 20.5 millions - Woolf's engine at Wheal Abraham, however, performed 34 millions - and in December 1815, 52 millions; and in May 1816, 57 millions; while the average duty of all the engines reported in Cornwall was 23 millions.
In 1820, Mr. Woolf erected engines at the Consolidated Mines having cylinders of 90 inches in diameter, and a stroke of 10 feet - the most powerful that had ever been constructed.
In December, 1827, a trial took place with one of Woolf's 90-inch engines, and it performed a duty of 63.5 millions - the average duty of 47 engines reported in this year was 32 millions, For some years before his death he received a pension of 100 pounds a year from the proprietors of the Consolidated Mines.
His name is associated with the improvements in the drainage of the Cornish mines; and whatever share posterity may assign to his individual genius in these improvements, his name is recorded in the page of history among those who have dedicated their talents and the opportunities of a long life to the advancement of practical science.
'THE LIFE AND LABOURS OF ARTHUR WOOLF
THE INVENTIVE CORNISH ENGINEER.
An interesting paper, "On the Life and Labours of Arthur Woolf, of Camborne," by Mr. S. Hocking, C.E., of Lower Rosewarne, near that place, his nephew and pupil, was read Mr. J. H. Collins, F.G.S., the honorary secretary of the Miners’ Association of Comwall and Devon, at its quarterly meeting, which was held in the large museum of the Royal Cornwall Geological Society’s building, Penzance. The following is an outline of the paper :
Woolf’s biography has not yet been written, and he is, therefore, less known to Cornishmen than some of his contemporaries, although he conferred substantial benefits on his native country and the world in general by his improvements in the steam-engine. He was baptized at Camborne, November 4th, 1766, his father, Arthur Woolf, being a bal carpenter. The future engineer was bound apprentice to a carpenter and joiner, at Pool. Having served out his indentures, he removed to London, and soon obtained employment as a millwright, which led to a situation as a first-class man at Bramah’s celebrated engineering works at Pimlico, where the talented Henry Maudslay was his fellow-workman. Together they left Bramah’s, each to start as an engineer on his own account. In 1796, a Durham colliery-owner employed Woolf to erect a second-hand Bolton and Watt engine at Newbottle, on the condition that he was to make it consume less fuel. This he successfully accomplished, his early familiarity with Cornish steam-engines having added to his fitness for such an undertaking. Having the next year assisted Hornblower over a difficulty with his two-cylinder engine at Meux’s London Brewery, he was appointed resident engineer, and held the situation for nine years. In the year 1806 he started, with a Mr. Edwards, a steam-engine factory on his own account. While Meux’s brewery, he patented a cast-iron boiler to resist high -pressure steam. The brewery books show that he was resident engineer there from April, 1797, to October, 1806 — dates which are relied on to correct an influential statement that he was a workman of Trevithick’s, and sent to London with one of that Cornishman’s high-pressure engines, and was, as late 1803, paid by Trevithick at the rate of £30 a year. Woolf was not in the country at that time, and was paid £3 a week by Messrs. Meux and Co. In 1804 he patented his mode of working high-pressure steam, and Watt's condenser to Hornblower’s two-cylinder engine. With one of these, a 36-horse power, he did the work of the brewery, consuming 36 bushels of coal per day. After he left, a 30-horse power Bolton and Watt replaced his engine. To effect the same amount per diem it consumed 84 bushels of coal. In a subsequent corn-grinding test, before Trevithick, Penn, and Henry Harvey, Woolf’s engine ground above 17 bushels of wheat for each bushel of coals consumed ; while a Bolton and Watt ground not quite six bushels of wheat for each bushel of coal; or 36,000,000 to 40,000,000 of duty to 12,000,000 or 13,000,000. In 1812 Woolf returned to Cornwall. His partner established himself in France as a maker of Woolf’s engines and boilers. The boiler is still the type of those in general use in France, and, Mr. Hocking adds, ought to better known in England.
Stamping of ores by steam-power was first introduced by Woolf ; he erected one of his patent engines for that purpose at Wheal Fanny, now the Cara Brea mine, in 1813-14, afterwards in several other mines. The large-size pumping-engines erected at the Wheal Abraham and the Wheal Vor in 1814 and 1815, successfully proved the value of Woolf’s inventions and established his reputation as the ablest of Cornish engineers. The very great advance he made in the duty done by bushel of coal, raising it from about 2,000,000 to 60,000,000, served to stimulate other engineers, as will be seen from the following quotation from an article on the History of the Cornish Engine, by James Sims, C.E., published in the "Mining Almanack" for 1849. "I commenced engineering," says M. Sims, "in year the 1811, at a period when the steam-engine was in a very rude state, and from that time up to 1814 little or no improvement took place." The average was for 1812, 19.3 millions; for 1813, 19.5 millions ; and 1814, 20.6 millions. In the latter part of 1814 Mr. Arthur Woolf erected one of his patent combined cylinder engines, and with great success. The duty of Woolf's engine having risen to 52.3 millions of pounds lifted one foot high by the consumption of one bushel of coal; and he having made several important improvements to Boulton and Watt engines, by causing them to work more expansively, by using higher pressure steam, awaked the whole of the Cornish engineers to a new era in steam-power. This statement must be considered highly complimentary to the abilities of Woolf, coming, as it does, from one of his most active opponents in engineering practice in Cornwall, Early in the year 1815 Woolf was employed by the managers of Dolcoath Mine to report upon the efficiency of the steam-boilers belonging to their large engine, as there was a difficulty in getting steam from them in sufficient quantity to meet the requirements of the engine, which was getting heavier loaded as the mine deepened. He found the boilers of ample capadty, and coal enough consumed to give the necessary quantity of steam; and the fact of their not doing so was proof to him that much of the heat was escaping to the chimney, which, on examination, he found was the fact. He simply removed the outlet passage to the chimney from the highest part of the flue to the lowest, when it was found the steam-giving power of the boilers under the altered condition had so increased as to render it unnecessary to add the contemplated new boiler.
Dolcoath new engine, erected by Jeffrey and Gribble in 1816, has often been referred to to show how near other engineers, using single cylinders (Boulton and Watt) form, approached the duty done by Woolf's two-cylinder engines. Woolf found in Gribble one of the most promising young men for his profession met with in Cornwall, and ever felt a pleasure in assisting him. Every drawing for the construction of the said Dolcoath new engine was by Gribble submitted to Woolf, as his personal friend, for approval, &c. Hence the complete success of this engine, for it was constructed in conformity with Woolf's patent, dated June 7, 1804, wherein a portion of his specification reads as follows "Fifthly, with regard to steam-engines in which the separate steam measure may not be thought advisable, the same may be improved the application of aforesaid discovery by making the boiler and steam-case in which the cylinder is enclosed stronger than usual, and altering the structure and dimensions of the valve admitting steam from the boiler into the cylinder in such a manner as that the steam may be admitted very gradually first, afterwards more freely. The reason for this precaution is this — steam of such great elastic force as I employ, if admitted into the cylinder, would strike with a force that would endanger the safety and durability of the engine. Due and effective means mustbe used to keep up the requisite temperature of all the parts of the apparatus into which the steam is admitted, not intended to be condensed." At the same time as Woolf commenced his practice in Cornwall there was no engine manufactory in the county that could supply such large castings as he required; they had to be brought from Wales, and were fitted up on the mines where they were to be employed. Most of the wrought-ironwork was forged, as well as fitted also, on the mines. Woolf had to train a staff of skilled workmen, selected from the most intelligent youths of the day. He was himself a first-class worker in metal and in wood, and was admirably endowed with qualities as a teacher. He constructed a good assortment of machine and hand tools, and worked them himself, with the help of his young men, until he could safely trust the tools in their hands.
Thus, in the Wheal Abraham commenced the school of mechanics that has since furished Cornwall and many other countries with skilled workmen and engineers. Seeing the need of a good engine manufactory in Cornwall, Mr. Woolf first thought of establishing one himself, but was persuaded by Messrs, Harvey and Co., of Hayle, to forego such an intention, and give that company the benefit of his knowledge in the enlargement of their little growing establishment, so as to make it serve his purpose. This work he undertook to do, and became the superintendent of the establishment; and this office he held up the time of his retirement, in 1833.
The considerable reputation acquired by Messrs. Harvey and Co. to that date was mainly due to the labours of Mr. Woolf. Mr. Woolf said, on being complimented in public company on his success in raising the duty from 20,000,000 to 52,000,000, that what he had done in that direction was but the starting point in progress, that some of the boys he had in training would make the steam-engine do 100,000,000, which prophesy has been realised. Of Mr. Woolf’s ability as an engineer and teacher of mechanics no man had better opportunities of judging than Mr. John Taylor, the able manager of the Consolidated and United Mines, in Gwennap; from whose statement, published in the work Cornish Engines, by Mr. Pole, the following extract is taken:- He (Mr. Woolf) made many valuable alterations in the details, among which may be mentioned the re-modelling of Mr. Horblower’s double-beat valve into the present improved form, introduced a style of manufacture greatly superior any that had been before known in the county, and formed, in fact, a new school of engineering there. He seemed to possess an almost inexhaustible mine of Invention. His improvements in detail were almost ennumerable, for scarcely a single part of the engine could be named, however apparently unimportant, which did not receive some beneficial alterations at his hands. His talent for contriving tools was very great, and he seemed to have an almost intuitive perception of the best methods of performing operations and processes of all kinds.”
In the limited space allowed for this paper a bare list of Mr. Woolf’s various engineering labours cannot given. There is, however, one little machine erected Messrs. Bolithos’ tanyard, in 1828, if working still would be a fit subject for description by a Penzance pupil for next year’s report. It consists of pumps to dram the tan-pits, worked by power at a distance, communicated through a column of water in a close pipe.
Mr. Collins remarked that one of the reasons why Woolf’s labours were not better appreciated in Cornwall was that his inventions very largely consisted of improvements in detail. He made possible some of almost the wildest speculations of his neighbours by introducing perfect workmanship and modifying details, so that one thing did not clash with the other. It was not so much that he introduced entirely new things but he carried them out to successful issue. If they examined the Cornish pumping engine of the very best construction at the present time they would find it full of small improvements, as they might seem, taken one at a time, but which in the main made that 100,000,000 of duty possible when Woolf himself only looked fora duty of 52,000,000. The man who does many small things is a greater benefactor to his species than he who strikes out on an entirely new path, but does not show how to follow it up. (Hear.)
Thanks were due to Mr Hocking for his paper.-" Mining Journal.”'
Sources of Information
-  Trevithick Society Newsletter No. 37, May 1982: 'A Little-known Woolf invention'
- Globe - Thursday 30 January 1812
- 1830 Institution of Civil Engineers
- 'Arthur Woolf - The Cornish Engineer 1766-1837' by T. T. Harris, D. Bradford Barton Ltd., 1966
- 1838 Institution of Civil Engineers: Obituaries
- The Cornish Telegraph - Wednesday 15 July 1874