He immediately resumed his habits of intense application. The rules which he laid down for himself, and which are still extant in his handwriting, prescribe sixteen hours a day of close application, and prove, not only the great mental power, but also the extraordinary physical strength he must have possessed, and for which indeed, during his residence at the university, he had been remarkable. During the period allotted to his preliminary studies, he read over and over again all the year-books, reports, and law treatises in print, and at the Tower of London and other antiquarian repositories examined and carefully studied the records from the foundation of the English monarchy down to his own time. Even the common-place book which he composed as the result of his study and research may, according to Lord Campbell, “be considered a corpus juris embracing and methodizing all that an English lawyer on any emergency could desire to know.” But Hale did not confine himself to law. He dedicated no small portion of his time to the study of pure mathematics, to investigations in physics and chemistry, and even to anatomy and architecture; and there can be no doubt that this varied learning enhanced considerably the value of many of his judicial decisions.

Hale was called to the bar in 1637, and almost at once found himself in full practice. Though neither a fluent speaker nor bold pleader, in a very few years he was at the head of his profession. He entered public life at perhaps the most critical period of English history. Two parties were contending in the state, and their obstinacy could not fail to produce a most direful collision. But amidst the confusion Hale steered a middle course, rising in reputation, and an object of solicitation from both parties. Taking Pomponius Atticus as his political model, he was persuaded that a man, a lawyer, and a judge could best serve his country and benefit his countrymen by holding aloof from partisanship and its violent prejudices, which are so apt to distort and confuse the judgment. But he is best vindicated from the charges of selfishness and cowardice by the thoughts and meditations contained in his private diaries and papers, where the purity and honour of his motives are clearly seen. It has been said, but without certainty, that Hale was engaged as counsel for the earl of Strafford; he certainly acted for Archbishop Laud, Lord Maguire, Christopher Love, the duke of Hamilton, and others. It is also said that he was ready to plead on the side of Charles I. had that monarch submitted to the court. The parliament having gained the ascendency, Hale signed the Solemn League and Covenant, and was a member of the famous Assembly of Divines at Westminster in 1644; but although he would undoubtedly have preferred a Presbyterian form of church government, he had no serious objection to the system of modified Episcopacy proposed by Ussher. Consistently with his desire to remain neutral, Hale took the engagement to the Commonwealth as he had done to the king, and in 1653, already serjeant, he became a judge in the Court of Common Fleas. Two years afterwards he sat in Cromwell’s parliament as one of the members for Gloucestershire. After the death of the Protector, however, he declined to act as a judge under Richard Cromwell, although he represented Oxford in Richard’s parliament. At the Restoration in 1660 Hale was very graciously received by Charles II., and in the same year was appointed chief baron of the exchequer, and accepted, with extreme reluctance, the honour of knighthood. After holding the office of chief baron for eleven years he was raised to the higher dignity of lord chief-justice, which he held till February 1676, when his failing health compelled him to resign. He retired to his native Alderley, where he died on December 25th of the same year. He was twice married, and survived all his ten children save two.

As a judge, Sir Matthew Hale discharged his duties with resolute independence and careful diligence. Lord Campbell says of him that “he is certainly to be considered the most eminent judge who ever filled the office [of chief baron]; and being promoted to be chief-justice of England, he gave new dignity to the supreme magistracy which had been illustrated by Gascoigne, by Fortescue, and by Coke.” His sincere piety made him the intimate friend of Barrow, Tillotson, Wilkins, and Stillingfleet, as well as of the Nonconformist leader Baxter. He is chargeable, however, with the condemnation and execution of two poor women tried before him for witchcraft in 1664, a kind of judicial murder then falling under disuse. He is also reproached with having hastened the execution of a soldier for whom he had reason to believe a pardon was preparing.

Of Hale’s legal works the only two of importance are his Historia Placitorum Coronae, or History of the Pleas of the Crown, first published, in 1739; and the History of the Common Law of England, with an Analysis of the Law, &c., 1713. Among his numerous religious writings the Contemplations, Moral and Divine, occupy the first place. Others are The Primitive Origination of Man, 1677; Of the Nature of True Religion, &c., 1684; A Brief Abstract of the Christian Religion, 1688. One of his most popular works is the collection of Letters of Advice to his Children and Grandchildren. He also wrote an Essay touching the Gravitation and Nongravitation of Fluid Bodies, 1673; Difficiles Nugae, or Observations touching the Torricellian Experiment, &c., 1675; and a translation of the Life of Pomponius Atticus, by Cornelius Nepos. His efforts in poetry were inauspicious. He left his valuable collection of MSS. and records to the library of Lincoln’s Inn. His life has been written by Burnet, 1682; by Williams, 1835; by Roscoe, in his Lives of Eminent Lawyers, in 1838; and by Lord Campbell, in hisZ⅛es of the Chief Justices

Hales is celebrated as the inventor of a “ventilator,” by means of which fresh air was introduced into jails, hospitals, mines, ships’ holds, &c. In the four years (1749-52) after its introduction into the Savoy prison, only 4 prisoners died; while previously the mortality had been from 50 to 100 per annum. The invention met with immediate favour, especially in France. Hales was the designer of other inventions by means of which sea-water was distilled, corn cleaned and preserved, meat preserved on long voyages, &c.

His chief writings are his Statical Essays (see Chemistry, vol. V. p. 461), consisting of Vegetable Staticks, or an Account of some Statical Experiments on the Sap in Vegetables (1727), and Hoemo- staticks, or an Account of Hydraulick and Hydrostatick Experiments made on the Blood and Blood-vessels of Animals (1733). His essay on The Means of Dissolving the Stone in the Bladder, &c., gained him the Copley gold medal in 1737. His Admonition to the Drinkers of Gin, Brandy, &c., appeared in 1734; the Vegetable Staticks, translated by Buffon, in 1735, and the Hoemostaticks, by Μ. de Sauvages, in 1744. For sketch of his life, with portrait, see Gardener's Chronicle, 1877, pp. 16-17.