ramparts and intrenchments. The Dee estuary is some miles wide here, but shallow and narrow at low water. Vessels of 300 tons reach the town. The principal exports are coal and lead from mines in the vicinity, which afford the chief employment. Roman relics and traces of Roman lead smelting-works have been found here. On a low freestone rock in a tidal marsh are the remains of a castle, built by Henry II, and dismantled 1647. The double tower or keep is 40 ft. in diameter, and includes two concentric walls, each 6 ft. thick, with an intervening gallery 8 ft. broad; within, is a circle 20 ft. in diameter, with four entrances. Deterioration of the channel of the Dee has made F. in a great degree a port of Chester, and here larger vessels, especially with timber, are discharged, and the cargoes floated up the Dee in smaller vessels, the timber in rafts. Pop. of F. (1891) 5,247.

F.

FLINT: a mineral which may be regarded as a variety of quartz, or as intermediate between quartz and opal, consisting almost entirely of silica, with a very little lime, oxide of iron, water, carbon, and sometimes even traces of organic matter. It has a flat shell-like fracture, is translucent or semi-transparent, and varies in color from a very dark brown, or almost black, to light brown, red, yellow, and grayish white, and is sometimes veined, clouded, marbled, or spotted. Dark colored flints are most freqnent in the chalk, in which principally F. occurs imbedded, forming nodules of various sizes, sometimes large nodular masses, of irregular, often grotesque shape; but gravel formed of lightcolored flints is very common, and it is disputed whether or not a change of color has taken place by exposure to atmospheric and other chemical agencies. F. is found sometimes in beds or veins. It is very abundant wherever the chalk formation extends, in England and other countries; rolled F. nodules are often found also in compound rocks, and vast alluvial tracts are sometimes full of them. geodes often contain crystals of quartz. F. nodules are usually moist in the interior if broken when newly taken from their beds. F. is sometimes harder than quartz sufficiently so to scratch it. The readiness with which it strikes fire with steel is well known, and it seems that the sparks are not all merely incandescent particles, heated by the friction, but that in some of them a chemical combination of silica and iron takes place, causing great increase of heat. The use of the F. and steel for igniting tinder, formerly common, has been almost superseded by that of lucifermatches, and gun-flints have given place to percussion caps. According to Piny, Clias was the first who struck fire with dint; or more probably, he was the first to show its application to useful purposes; and he therefore received the name Pyrodes. The most ancient use of F. was probably for sharp weapons and cutting instruments; and F. knives, axes, arrow heads, etc, are among the most interesting relics of rude antiquity: see FLINT IMPLEMENTS. present, a principal use of F. is in the manufacture of fine earthenware, into the composition of which it enters being for this purpose first calcined, then thrown into cold water. and afterwards powdered.

At

The origin of F. is a difficult question. Silicious de posits are sometimes a purely chemical operation, as in the case of the silicious sinter formed round the geysers of Ice land, from the evaporation of water largely charged with silex. But at the bottom of the sea, as no evaporation could take place, some other agent than springs of water saturated with silex must have supplied the materials. It is a fact of considerable importance in this inquiry, that almost all large masses of limestone have thin silicious concretions, or flints. Thus, chert is found in carboniferous and other limestones, and menilite in the tertiary limestones of the Paris basin. The conditions necessary for the deposition of calcareous strata seem to be those required for the formation of silicious concretions. The materials of both exist in solution in sea-water, and as it needed the foraminifer, the coral, and the mollusk to fix the carbonate of lime which formed the chalk deposits, so the silex was secreted by innumerable diatoms and sponges, and their remains most probably supplied the material of the flint. The discovery by Dr. Bowerbank and other microscopists of the spicules of sponges and the frustules of diatoms in almost every specimen of F., has clearly shown that F. to a large extent, if not entirely, owes its origin to these minute. organisms. It is, however, difficult to account for the changes that have taken place in these materials subsequent to their deposition.

FLINT, AUSTIN, M.D., LL.D.: 1812, Oct. 20-1886, Mar 13; b Petersham, Mass.: physician and author. He gradu ated in the medical dept. of Harvard Univ. 1833, practiced in Northampton, Boston, and Buffalo. till 1844; was prof. of the institutes and practice of medicine in Rush Medical College, Chicago, 1844-46; established the Buffalo Medical Journal 1846, and was a founder of buffalo Medical College 1847. During 1847-52 he was prof. of the theory and practice of medicine and of clinical medicine at Buffalo, 1852-56 occupied a similar chair in the medical dept. of Louisville Univ, 1856-58 was prof. of pathology and clinical medicine at Bulalo, and 1858-61 (winters) was prof. of clinical medicine in the New Orleans Medical School, and visiting physician to the Charity Hospital. He removed to New York 1859 and became prof. of pathology and practical medicine in the Long Island College Hospital, prof. of the theory and practice of medicine in the medical college of Bellevue Hospital, and visiting physician to the hospital. The former office he held till 1868, the others till death. Subsequently he became consulting physician to the Charity, St. Mary's, and St. Elizabeth's hospitals, and the Hospital for the Ruptured and Crippled. He was pres. of the New York Acad. of Medicine 1872-85, pres. of the American Medical Assoc. 1884, and delegate to the medical congresses, Philadelphia (international) 1876, London 1881, and Copenhagen 1884; and had been elected pres. of the one to be held in Washington 1887. He was author of many standard professional works.

FLINT, AUSTIN, Jr., M.D.: prof. and author; b. North:

ampton, Mass., 1836, Mar. 28. He studied at Buffalo, Harvard Univ., Louisville, and Philadelphia, and graduated at the Jefferson Medical College, Philadelphia, 1857. He became an attending surgeon in the Buffalo City Hospital and prof. of physiology in the medical college there 1858, removed to New York with his father 1859, and was elected prof. of physiology in the New York Medical College and the New Orleans School of Medicine. He passed a part of 1861 in special study with Charles Robin and Claude Bernard in Paris, and in the same year was elected prof. of physiol. ogy and microscopic anatomy in the new medical college of Bellevue Hospital, and sec. and treas. of the faculty. Dr. F. lectured on physiology in the Long Island College Hospital eight years, and was appointed surgeon-gen. of N. Y. 1874. His published works include The Fhysiology of Man, 5 vols. (1866-74); Manual of Chemical Examination of Urine in Disease (1870, 84); Text-book of Human Physiology (1876, 81); The Source of Muscular Power (1878); and The Physiological Effects of Severe and Protracted Muscular Exercise. His A New Excretory Function of the Liver (1869) received honorable mention and a prize of 1,500 fr. from the French Acad. of Sciences.

FLINT, TIMOTHY: 1780-1840, Aug. 16; b. Reading, Mass. He graduated at Harvard College, and 1802-14 was minister of the Congl. Church in Lunenburg, Mass. He was a missionary for the valley of the Mississippi, 1815-25. Returning to the northern states, published Recollections of Ten Years Passed in the Valley of the Mississippi (Boston, 8vo, 1826); also a novel of adventure in the first Mexican revolution, Francis Berrian. In 1828, he issued two works: A Condensed Geography and History of the Western States in the Mississippi Valley (Cincinnati, 2 vols. 8vo); and Arthur Clenning, a novel (Philadelphia, 2 vols. 8vo). In 1833, he edited several numbers of the Knickerbocker Magazine, and was subsequently editor for three years of The Western Monthly Magazine. Others of his works, besides novels, are: Indian Wars in the West (1833, 12mo), Lectures on Natural History, Geology, Chemistry, and the Arts (Boston 1833, 12mo); translation of Droy's L'Art d'étre Heureuse, with additions by translator; and Biographical Memoir of Daniel Boone, the First Settler of Kentucky (Cincinnati 1834, 18mo). In 1835, he contributed to the London Athenaeum a series of Sketches of the Literature of the United States. He died at Salem.

FLINT IMPLEMENTS: believed to have been used by the primitive inhabitants in very many countries, have from time to time been turned up by the plow, dug out from ancient graves, fortifications, and dwelling-places, or fished up from the beds of lakes and rivers. They do not differ, in any material respect, from the flint implements and weapons still in use among uncivilized tribes in Asia, Africa, America, and the islands of the Pacific Ocean. The weapons of most frequent occurrence are arrow-heads (see ELF ARROWS), spear-points, dagger-blades, and ax-heads or Celts (q.v.). The more common implements are knives, chisels, rasps, wedges, and thin curved, or semicircular plates, to which the name of scrapers' has been given. There is great variety in the size and in the shape, even of articles of the same kind, and equal variety in the amount of skill or labor expended in their manufacture. In some instances, the flint has been roughly fashioned into something like the required form by two or three blows; in others, it has been laboriously chipped into the wished for shape, often one of some elegance. In yet another class, the flint, after being duly shaped, has been ground smooth, or has even received as high a polish as could be given by a modern lapidary. Examples of all the varieties of flint weapons and implements are in numerous collections in the United States, in the British Museum, in the Museum of the Royal Irish Acad. at Dublin, in the Museum of the Soc. of Antiquaries of Scotland at Edinburgh, and above all, in the Museum of the Royal Soc. of Antiquaries at Copenhagen, which is especially rich in this class of remains. See Catalogue of the Archeological Museum at Edinburgh in 1856 Edin 1859); Wilde's Catalogue of the Antiquities in the Museum of the Royal Irish Academy (Dubl. 1857-61); Worsaae's Nordiske Oldsager i det Kongelige Museum i Kjobenhavn (Copen 1859); and Frederic Troyon's Habitations Lacustres (Lausanne, 1860).

Geological discoveries have recently invested flint implements with a new interest. At Abbeville, at Amiens, at Paris, and elsewhere on the European continent, flint weapons, fashioned by the hand of man, have been found with remains of extinct species of the elephant, the rhinoceros, and other mammals, in undisturbed beds of those deposits of sand, gravel, and clay to which geologists have given the name of the drift.' They resemble the flint implements and weapons found on the surface of the earth, but are generally larger, of ruder workmanship, and less varied in shape. They have been divided into three classes-round pointed, as in tig. 1; and sharp-pointed, as in fig. 2, both being chipped to a sharp edge, so as to cut or pierce only at the pointed end; and oval-shaped, as in fig. 3, with a cutting edge all round. The first and second classes vary in length from about four inches to eight or nine inches; the third class is generally four or five inches long, but specimens have been found of no more than two inches, and of as much as eight or nine inches. In no instance has any flint implement discovered in the drift been found either polished or ground. The French antiquary, M,

Boucher de Perthes, was the first to call attention to these very interesting remains, in his Antiquités Celtiques et Antédiluviennes (Paris 1847-57). But it has since been remembered that precisely similar implements were found in a similar position at Hoxne, in Suffolk, England, with remains of some gigantic animal, in 1797; and at Gray's Inn Lane, in London, with remains of an elephant, in 1715.

To what age these remains should be assigned, is a question on which geology seems scarcely yet prepared to speak

Flint Implements from the Valley of the Somme--Reduced.

with authority. But, in the words of Mr. John Evans, in his essay on Flint Implements in the Drift,' in the Arche ologia, xxxviii. (Lond. 1860), thus much appears to be estab lished beyond a doubt, that in a period of antiquity remote beyond any of which we have hitherto found traces, this portion of the globe was peopled by man; and that mankind has here witnessed some of those geological changes by which the so-called diluvial beds were deposited. Whether these were the result of some violent rush of