grass-covered hills as in the Downs of southern England and the Wolds of Yorkshire and Lincolnshire. The hills are often intersected by clean-cut dry valleys. It forms fine cliffs on the coast of Kent, Yorkshire and Devonshire.
Chalk is employed medicinally as a very mild astringent either alone or more usually with other astringents. It is more often used, however, for a purely mechanical action, as in the preparation hydrargyrum cum creta. As an antacid its use has been replaced by other drugs.
Black chalk or drawing slate is a soft carbonaceous schist, which gives a black streak, so that it can be used for drawing or writing. Brown chalk is a kind of umber. Red chalk or reddle is an impure earthy variety of haematite. French chalk is a soft variety of steatite, a hydrated magnesium silicate.
The most comprehensive account of the British chalk is contained in the Memoirs of the Geological Survey of the United Kingdom, “The Cretaceous Rocks of Britain,” vol. ii. 1903, vol. iii. 1904 (with bibliography), by Jukes-Browne and Hill. See also “The White Chalk of the English Coast,” several papers in the Proceedings of the Geologists’ Association, London, (1) Kent and Sussex, xvi. 1900, (2) Dorset, xvii., 1901, (3) Devon, xviii., 1903, (4) Yorkshire, xviii., 1904. (J. A. H.)
CHALKHILL, JOHN (fl. 1600?), English poet. Two songs by him are included in Izaak Walton’s Compleat Angler, and in 1683 appeared “Thealma and Clearchus. A Pastoral History in smooth and easie Verse. Written long since by John Chalkhill, Esq., an Acquaintant and Friend of Edmund Spencer” (1683), with a preface written five years earlier by Walton. Another poem, “Alcilia, Philoparthens Loving Follie” (1595, reprinted in vol. x. of the Jahrbuch des deutschen Shakespeare-Vereins), was at one time attributed to him. Nothing further is known of the poet, but a person of his name occurs as one of the coroners for Middlesex in the later years of Queen Elizabeth’s reign. Professor Saintsbury, who included Thealma and Clearchus in vol. ii. of his Minor Poets of the Caroline Period (Oxford, 1906), points out a marked resemblance between his work and that of William Chamberlayne.
CHALKING THE DOOR, a Scottish custom of landlord and tenant law. In former days the law was that “a burgh officer, in presence of witnesses, chalks the most patent door forty days before Whit Sunday, having made out an execution of ’chalking,' in which his name must be inserted, and which must be subscribed by himself and two witnesses.” This ceremony now proceeds simply on the verbal order of the proprietor. The execution of chalking is a warrant under which decree of removal will be pronounced by the burgh court, in virtue of which the tenant may be ejected on the expiration of a charge of six days.
CHALLAMEL, JEAN BAPTISTE MARIUS AUGUSTIN (1818–1894), French historian, was born in Paris on the 18th of March 1818. His writings consist chiefly of popular works, which enjoyed great success. The value of some of his books is enhanced by numerous illustrations, e.g. Histoire-museé de la Révolution française, which appeared in 50 numbers in 1841–1842 (3rd ed., in 72 numbers, 1857–1858); Histoire de la mode en France; la toilette des femmes depuis l’époque gallo-romaine jusqu’à nos jours (1874, with 12 plates; new ed., 1880, with 21 coloured plates). His Mémoires du peuple française (1865–1873) and La France et les Français a travers les siécles (1882) at least have the merit of being among the first books written on the social history of France. In this sense Challamel was a pioneer, of no great originality, it is true, but at any rate of fairly wide information. He died on the 20th of October 1894.
CHALLEMEL-LACOUR, PAUL AMAND (1827–1896), French statesman, was born at Avranches on the 19th of May 1827. After passing through the École Normale Supérieure he became professor of philosophy successively at Pau and at Limoges. The coup d’état of 1851 caused his expulsion from France for his republican opinions. He travelled on the continent, and in 1856 settled down as professor of French literature at the Polytechnic of Zürich. The amnesty of 1859 enabled him to return to France, but a projected course of lectures on history and art was immediately suppressed. He now supported himself by his pen, and became a regular contributor to the reviews. On the fall of the Second Empire in September 1870 the government of national defence appointed him prefect of the department of the Rhone, in which capacity he had to suppress the Communist rising at Lyons. Resigning his post on the 5th of February 1871, he was in January 1872 elected to the National Assembly, and in 1876 to the Senate. He sat at first on the Extreme Left; but his philosophic and critical temperament was not in harmony with the recklessness of French radicalism, and his attitude towards political questions underwent a steady modification, till the close of his life saw him the foremost representative of moderate republicanism. During Gambetta’s lifetime, however, Challemel-Lacour was one of his warmest supporters, and he was for a time editor of Gambetta’s organ, the République française. In 1879 he was appointed French ambassador at Bern, and in 1880 was transferred to London; but he lacked the suppleness and command of temper necessary to a successful diplomatist. He resigned in 1882, and in February 1883 became minister of foreign affairs in the Jules Ferry cabinet, but retired in November of the same year. In 1890 he was elected vice-president of the Senate, and in 1893 succeeded Jules Ferry as its president. His influence over that body was largely due to his clear and reasoned eloquence, which placed him at the head of contemporary French orators. In 1893 he also became a member of the French Academy. He distinguished himself by the vigour with which he upheld the Senate against the encroachments of the chamber, but in 1895 failing health forced him to resign, and he died in Paris on the 26th of October 1896. He published a translation of A. Heinrich Ritter’s Geschichte der Philosophie (1861); La Philosophie individualiste: étude sur Guillaume de Humboldt (1864); and an edition of the works of Madame d’Épinay (1869).
In 1897 appeared Joseph Reinach’s edition of the Œuvres oratoires de Challemel-Lacour.
CHALLENGE (O. Fr. chalonge, calenge, &c., from Lat. calumnia, originally meaning trickery, from calvi, to deceive, hence a false accusation, a “calumny”), originally a charge against a person or a claim to anything, a defiance. The term is now particularly used of an invitation to a trial of skill in any contest, or to a trial by combat as a vindication of personal honour (see Duel), and, in law, of the objection to the members of a jury allowed in a civil action or in a criminal trial (see Jury).
“ CHALLENGER ” EXPEDITION. The scientific results of several short expeditions between 1860 and 1870 encouraged the council of the Royal Society to approach the British government, on the suggestion of Sir George Richards, hydrographer to the admiralty, with a view to commissioning a vessel for a prolonged cruise for oceanic exploration. The government detailed H.M.S. “Challenger,” a wooden corvette of 2306 tons, for the purpose. Captain (afterwards Sir) George Nares was placed in command, with a naval crew; and a scientific staff was selected by the society with Professor (afterwards Sir) C. Wyville Thomson as director. The staff included Mr (afterwards Sir) John Murray and Mr H. N. Moseley, biologists; Dr von Willemoes-Suhm, Commander Tizard, and Mr J. Y. Buchanan, chemist and geologist. A complete scheme of instructions was drawn up by the society. The “Challenger” sailed from Portsmouth in December 1872. For nearly a year the work of the expedition lay in the Atlantic, which was crossed several times. Teneriffe, the Bermudas, the Azores, Madeira, the Cape Verd Islands, Bahia and Tristan da Cunha were successively visited, and in October 1873 the ship reached Cape Town. Steering then south-east and east she visited the various islands between 45° and 50° S., and reached Kerguelen Island in January 1874. She next proceeded southward about the meridian of 80° E. She was the first steamship to cross the Antarctic circle, but the attainment of a high southerly latitude was not an object of the voyage, and early in March the ship left the south polar regions and made for Melbourne. Extensive researches were now made in the Pacific. The route led by New Zealand, the Fiji Islands, Torres Strait, the Banda Sea, and the China Sea to Hong Kong. The western Pacific was then explored northward to Yokohama, after which the “Challenger” struck across the ocean by Honolulu and Tahiti to Valparaiso. She then coasted