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 second time, he returned to the United States, and practised his profession at Boston (1818–1830), and afterwards at Cambridge, Massachusetts, where he died on the 9th of July 1843. He was elected an associate of the Royal Academy in 1819. In colour and the management of light and shade Allston closely imitated the Venetian school, and he has hence been styled the “American Titian.” Many of his pictures have Biblical subjects, and Allston himself had a profoundly religious nature. His first considerable painting, “The Dead Man Revived,” executed shortly after his second visit to England, and now at the Pennsylvania Academy of Fine Arts in Philadelphia, gained a prize of 200 guineas. In England he also painted his “St Peter Liberated by the Angel,” “Uriel in the Sun” (at Stafford House), “Jacob’s Dream” (at Petworth) and “Elijah in the Wilderness.” To the period of his residence in America belong “The Prophet Jeremiah” (at Yale), “Saul and the Witch of Endor,” “Miriam,” “Beatrice,” “Rosalie,” “Spalatro’s Vision of the Bloody Hand,” and the vast but unfinished “Belshazzar’s Feast” (in the Boston Athenaeum), at which he was working at the time of his death. As a writer, Allston shows great facility of expression and imaginative power. His friend Coleridge (a portrait of whom by Allston is in the National Gallery) said of him that he was surpassed by no man of his age in artistic and poetic genius. His literary works are–The Sylphs of the Seasons and other Poems (1813), where he displays true sympathy with nature and deep knowledge of the human heart; Monaldi (1841), a tragical romance, the scene of which is laid in Italy; and Lectures on Art, edited by his brother-in-law, R. H. Dana the novelist (1850).

ALLUVION (Lat. alluvio, washing against), a word taken from Roman law, in which it was one of the examples of accessio, that is, acquisition of property without any act being done by the acquirer. It signifies the gradual accretion of land or formation of an island by imperceptible degrees. If the accretion or formation be by a torrent or flood, the property in the severed portion or new island continues with the original owner until the trees, if any, swept away with it take root in the ground. Alluvion never attached at all in the case of agri limitati, that is, lands belonging to the state and leased or sold in plots. Dig. xli. 1, 7, is the main authority. English law is in general agreement (except as to agri limitati) with Roman, as appears from the judgment in Foster v. Wright, 1878, 4 C.P.D. 438. The Scottish law, as laid down by the House of Lords in Earl of Zetland v. Glover Incorporation, 1872, L.R. 2 H.L., Sc., 70, is in accordance with the English. (See .)

ALLUVIUM, soil or land deposited by running water. All streams, from the tiniest rill to the greatest river, are continually engaged in transporting downstream solid particles of rock, the product of weathering agencies in the area which they drain. Since the capacity of a stream to carry matter in suspension is proportional to its velocity, it follows that any circumstance tending to retard the rate of flow will induce deposition. Thus a fall in the gradient at any point in the course of a stream; any snag, projection or dam, impeding the current; the reduced velocity caused by the overflowing of streams in flood and the dissipation of their energy where they enter a lake or the sea, are all contributing causes to alluviation, or the deposition of stream-borne sediment. It is evident from the foregoing remarks, that while even the smallest stream may make deposits of alluvial character it is in the flood-plains and deltas of large rivers that the great alluvial deposits are to be found. The finer material constituting alluvium, often described as “silt,” is sand and mud. Although it may be exceedingly fine-grained, there is usually very little clay in alluvium. The larger materials include gravel of all degrees of coarseness; carbonaceous matter is often an important element. The amount of solid matter borne by large streams is enormous; many rivers derive their names from the colour thereby imparted to the water, e.g. Hwang Ho＝Yellow river, Missouri＝Big Muddy, the Red river, &c. It has been estimated that the Mississippi annually carries 406 million tons of sediment to the sea; the Hwang Ho 796 million tons; the Po

67 million tons. Many shallow lakes have been completely filled with alluvium and their sites are now occupied by fertile plains; this process may be seen in operation almost anywhere; a good illustration is the delta of the Rhone in Lake Geneva. Alluvial deposits may be of great size. The flood-plain of the Mississippi has an area of 50,000 sq. m.; the great delta of the Ganges and Brahmaputra has an area of about 60,000 sq. m.; that of the Hwang Ho reaches out 300 m. into the sea and has a coastal border of about 400 m. Old alluvial deposits are left high above the existing level of many rivers, in the form of “terraces” of gravel and loam, the streams to which these owe their existence having modified their courses and cut deeper channels; such are the alluvial gravels and brick-earths upon which much of “greater London” is built. In some regions alluvial deposits are the resting places of gemstones and gold, platinum, &c.; it is from these deposits that the largest nuggets of gold have been obtained. Alluvial soils are almost invariably of great fertility; it is due to the alluvial mud annually deposited by the Nile that the dwellers in Egypt have been able to grow their crops for over 4000 years without artificial fertilization.

ALLYL ALCOHOL, C3H5OH or CH2:CH·CH2OH, a compound which occurs in very small quantities in wood spirit. It may be prepared from allyl iodide by the action of moist silver oxide; by the reduction of acrolein; or by heating glycerin with oxalic acid and a little ammonium chloride to 260° C. In this last reaction glycerol monoformin is produced as an intermediate product, but is decomposed as the temperature rises:—

It is a colourless mobile liquid of pungent smell, boiling at 97° C. Being an unsaturated compound it combines readily with the halogens. Oxidation by strong oxidizing agents converts it successively into its aldehyde, acrolein, and into acrylic acid. By gentle oxidation with potassium permanganate it may be converted into glycerin.

ALMA, a river of Russia, in the S.W. of the Crimea, entering the Black Sea 17 m. N. of Sevastopol. It gives its name to a famous victory gained over the Russians, on the 20th of September 1854, by the allied armies in the (q.v.). The south bank of the river is bordered by a long ridge, which becomes steeper as it approaches the sea, and upon this the Russians, under Prince Menshikov, were drawn up, to bar the Sevastopol road to the allies, who under General Lord Raglan and Marshal St Arnaud approached from the north over an open plain. The Russian commander massed his troops in heavy columns after the fashion of 1813, and drew in his left wing so that it should as far as possible be out of range of the allied men-of-war, which were sailing down the coast in line with their land forces. The allied generals decided that the French (right wing) and the Turks should attack Menshikov’s left, while the British, further inland, were to assault the front of the Russian position. The forces engaged are stated by Hamley (War in the Crimea) as, French and Turks, 35,000 infantry, with 68 guns; British, 23,000 infantry, 1000 cavalry and 60 guns; Russians, 33,000 infantry, 3800 cavalry and 120 guns; by the Austrian writer Berndt (Zahl im Kriege) the allied forces are reckoned at 57,000 men with 108 guns, and the Russians at 33,600 men with 96 guns. The French advance met at first with little opposition, and several divisions scaled the cliffs of the lower Alma without difficulty. Menshikov relied apparently on being able to detach his reserves to cope with them, but the assailants moved with a rapidity which he had not counted upon, and the Russians only came into action piecemeal in this quarter. Opposite the British, who as usual deployed at a distance and then advanced in long continuous lines, the Russians were posted on the crest of a long glacis-like slope, which offered but little dead ground to an assailant. The village of Burliuk, and the vineyards which bordered the river, were quickly cleared by the British skirmishers, and the line of battle behind them crossed, though with some difficulty. On emerging from the cover afforded by the river-bed the British divisions, now crowded together, but still