From Graces Guide
John Farey (1791-1853)
1791 Born in Lambeth, son of John Farey, geologist
1822 February. Marriage. John Farey, Junior, civil engineer to Miss Taylor both of Howland Street, Fitzroy Square.
1826 John Farey, Lincoln's Inn Fields, Civil Engineer, became a member of the Institution of Civil Engineers.
1851 Died in Sevenoaks
1852 Obituary 
Mr. John Farey was born in Lambeth, on the 20th March 1791, and was brought up and educated at Woburn, near the seat of Francis, Duke of Bedford, to whom his father was agent.
The interest taken by the Duke in Agriculture, and which eventually, with the efforts of the Board of Agriculture, contributed to the formation of the Royal Agricultural Society of England, induced Mr. Farey, sen., to devote much of his time to the subject, and he wrote several articles in the early numbers of the 'Agricultural Magazine;' he was regarded as an authority in geological questions, and being much employed in making reports in that capacity, was enabled to collect the materials for his survey of Derbyshire, which enjoyed, at that time, considerable reputation.
The literary engagements of the father naturally influenced the tastes of the children, and from the early age of fourteen, and many years subsequently, Mr. John Farey was, with his brother and sisters, engaged in making the drawings for the illustrative plates of Rees’ and the 'Edinburgh Encyclopedias,' 'Tilloch’s Magazine,' 'Gregory’s Mechanics,' and 'Mechanical Dictionary,' the 'Pantalogia,' and many other scientific works, several of which he either edited, or contributed articles to.
The patient industry and habits of laborious research, which were the leading features of his character: aided by a remarkably retentive memory, peculiarly fitted him for the duties of this position, and to him, in conjunction with Messrs. Lowries, the engravers, may, with justice, be ascribed, in a great degree, the merit of introducing a better style of illustration in our scientific works.
Here also he laid the foundation for one portion of his subsequent professional career, and in after years, when consulted on patent cases, the accuracy of his information, as to the principle and forms of machines, the minute details of processes, the names of inventors, and the dates of introduction, showed that the impressions of early life were indelibly fixed, and this mental store very rarely proved inadequate to the demands upon it.
The necessity of accomplishing a large number of drawings, with great accuracy, frequently within a limited time, naturally excited the inventive faculties, arid the result was, the introduction, in 1807, of an instrument for making perspective drawings, a description of which was published in the 'Transactions of the Society of Arts,' and was rewarded by the Silver Medal; and in 1813 he invented the machine for drawing ellipses, to which he subsequently made many additions, and for which the Gold Medal of the Society of Arts was awarded; he also introduced many improvements in the drawing instruments and scales, now generally in use.
He was introduced, at a very early age, to the most eminent engineers and scientific men of the period, among whom were Watt, Telford, Rennie, Jessop, Mylne, Bramah, Donkin, Brunel, Maudslay, Huddart, Bentham, Ramsden, Troughton, Davy, Wollaston, and Sir Joseph Banks, by whom, acting in conjunction with Messrs. Huddart, Jessop, Mylne, and Bennie, he was employed to prepare for publication, Smeaton's Reports and Drawings, the originals of which were accordingly intrusted to him for that purpose.
In 1819 he went to St. Petersburgh, and other parts of Russia, where he was engaged as a Civil Engineer in the construction of ironworks. There he first saw a steam-engine indicator, then attempted to be kept a profound secret: his inquiring disposition soon discovered the qualities of the instrument, with which he made many experiments; on his return to England, he employed M'Naught to construct them for general use, and thenceforth he was continually employed to use the instrument, in disputed cases of the power of steam-engines.
In 1821 he relinquished all his professional engagements in favour of his brother Joseph, and embarked in a lace manufactory, in Devonshire, which, however, he gave up in 1823, and in 1826 took the engineering direction of Messrs. Marshall's flax mills, at Leeds; this position he was obliged to relinquish in 1826, in consequence of the failure of his brother's health, and the necessity for his return to London, where he resumed his profession of consulting Civil Engineer, and from that time was engaged in most of the novel inventions, important trials in litigated patent cases, and scientific investigations, during the last quarter of a century.
For this branch of the profession, Mr. Farey was peculiarly qualified, by natural tastes, by early pursuits and subsequent engagements; and during a long and active career, it may be asserted, that however his opinions, or his decisions, may have been questioned by the losing party, the fearless honesty of his evidence was never once impugned, by either side. His laborious research into authority for cases, was proverbial, and his habits of order and regularity rendered his office and library models for these qualities. In this, as in the preparation of the drawings for specifications, he received invaluable assistance from Mrs. Varey, a lady of rare attainments, who to great amiability of disposition, and a thorough knowledge of the duties of her sex, joined almost masculine scientific attainments, which she employed as modestly, as profitably, in aiding the labours of her husband, who never fully recovered the shock occasioned by her decease.
Mr. Farey’s principal scientific work was a 'Treatise on the Steam Engine,’ giving in the first volume, which is all that has been published [See note below], a complete historical and practical account of the invention, from its first recorded origin, up to the period when Watt, Southern, and their contemporaries, resigned into other hands the management of the works at Soho, where had been nursed and raised to maturity that giant power, which has done so much for the welfare of nations, and to which it does not appear possible, at present, to assign any limit. The work abounds with useful information, and rules for calculation and constriction, and it is to be regretted that constant engagements, and, latterly, failing health, prevented the completion of the other volumes.
Mr. Farey joined the Institution, as a Member, in 1826; served several offices in the Council, took a very active part in the arrangement of the bye-laws, made several communications to, and participated in most of the discussions at the meetings, and was ever ready to devote any amount of time, or money, to the advancement of the welfare of the Institution, by the members of which he was universally esteemed, and in their minds he will ever be regarded as a good and upright man.
His health received a severe shock, at the time of the burning of his residence in Great Guildford Street, when considerable portions of his library and documents were injured, or destroyed, and he died on the 17th July, 1851, in his sixtieth year, beloved and regretted by all who knew him.
Note: Fortunately, Volume 2 of Farey's 'A Treatise on the Steam Engine' was published in 1971 by David & Charles, who reproduced in facsimile form the pages of the surviving proof copy, complete with Farey's hand-written annotations and correction.