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 Niger, S. by the Yoruba country, N.W. by Gurma. The country consists of an elevated plain traversed by rivers draining north or east to the Niger. The water-parting between the Niger basin and the coast streams of Dahomey and Lagos runs north-east and south-west near the western frontier. In about 10° N., below the town of Bussa, rapids block the course of the Niger, navigable up to that point from the sea. The soil is mostly fertile, and is fairly cultivated, producing in abundance millet, yams, plantains and limes. The acacia tree is common, and from it gum-arabic of good quality is obtained. From the nut of the horse-radish tree ben oil is expressed. Cattle are numerous and of excellent breed, and game is abundant. Borgu is inhabited by a number of pagan negro tribes, several of whom were dependent on the chief of Nikki, a town in the centre of the country, the chief being spoken of as sultan of Borgu. The king of Bussa was another more or less powerful potentate. In the early years of the 19th century Borgu was invaded by the (q.v.), but the Bariba (as the people are called collectively) maintained their independence. In 1894 Borgu became the object of rivalry between France and England. The Royal Niger Company, which had already concluded a treaty of protection with the king of Bussa, sent out Captain (afterwards Sir) F. D. Lugard to negotiate treaties with the king of Nikki and other chiefs, and Lugard succeeded in doing so a few days before the arrival of French expeditions from the west. Disregarding the British treaties, French officers concluded others with various chiefs, invaded Bussa and established themselves at various points on the Niger. To defend British interests, the West African Frontier Force was raised locally under Lugard’s command, and a period of great tension ensued, British and French troops facing one another at several places. A conflict was, however, averted, and by the convention of June 1898 the western part of Borgu was declared French and the eastern British, the French withdrawing from all places on the lower Niger.

The British portion of Borgu has an area of about 12,000 sq. m. Up to the period of inclusion within the protectorate of Nigeria little or nothing was known of the country, though there were interesting legends of the antiquity of its history. The population was entirely independent, and resisted with success not only the Fula from the north but also the armies of Dahomey and Mossi from the south and west. Travellers who attempted to penetrate this country had never returned. Since 1898 the country has been opened, and from being the most lawless and truculent of people the Bariba have become singularly amenable and law-abiding. Provincial courts are established, but there is little crime in the province. The British garrisons have been replaced by civil police. The assessment of taxes under British administration was successfully carried out in 1904, and taxes are collected without trouble. In south Borgu the people are agricultural but not industrious or inclined for trade. In the north there are some pastoral settlements of Fula. The Bariba themselves remain agricultural. Cart-roads have been constructed between the town of Kiama and the Niger. The agricultural resources of Borgu are great, and as the population increases with the cessation of war and by immigration the country should show marked development. Shea trees are abundant. Elephants are still to be found in the fifty-mile strip of forest land which stretches between the Niger and the interior of the province. The forest contains valuable sylvan products, and there are great possibilities for the cultivation of rubber. There are also extensive areas of fine land suitable for cotton, with the waterway of the Niger close at hand. Labour might be brought from Yorubaland close by, and a Yoruba colony has been experimentally started. (See and .)

BORIC ACID, or, H3BO3, an acid obtained by dissolving boron trioxide in water. It was first prepared by Wilhelm Homberg (1652–1715) from borax, by the action of mineral acids, and was given the name sal sedativum Hombergi. The presence of boric acid or its salts has been noted in sea-water, whilst it is also said to exist in plants and especially in almost all fruits (A. H. Allen, Analyst, 1904, 301). The free acid is found native in certain volcanic districts such as Tuscany, the Lipari Islands and Nevada, issuing mixed with steam from fissures in the ground; it is also found as a constituent of many minerals (borax, boracite, boronatrocalcite and colemanite).

The chief source of boric acid for commercial purposes is the Maremma of Tuscany, an extensive and desolate tract of country over which jets of vapour and heated gases (soffioni) and springs of boiling water spurt out from chasms and fissures. In some places the fissures open directly into the air, but in other parts of the district they are covered by small muddy lakes (lagoni). The soffioni contain a small quantity of boric acid (usually less than 0.1%), together with a certain amount of ammoniacal vapours. In order to obtain the acid, a series of basins is constructed over the vents, and so arranged as to permit of the passage of water through them by gravitation. Water is led into the highest basin and by the action of the heated gases is soon brought into a state of ebullition; after remaining in this basin for about a day, it is run off into the second one and is treated there in a similar manner. The operation is carried on through the entire series, until the liquor in the last basin contains about 2% of boric acid. It is then run into settling tanks, from which it next passes into the evaporating pans, which are shallow lead-lined pans heated by the gases of the soffioni. These pans are worked on a continuous system, the liquor in the first being concentrated and run off into a second, and so on, until it is sufficiently concentrated to crystallize. The crystals are purified by recrystallization from water. Artificial soffioni are sometimes prepared by boring through the rock until the fissures are reached, and the water so obtained is occasionally sufficiently impregnated with boric acid to be evaporated directly. Boric acid is also obtained from boronatrocalcite by treatment with sulphuric acid, followed by the evaporation of the solution so obtained. The residue is then heated in a current of superheated steam, in which the boric acid volatilizes and distils over. It may also be obtained by the decomposition of boracite with hot hydrochloric acid. In small quantities, it may be prepared by the addition of concentrated sulphuric acid to a cold saturated solution of borax.

Na2B4O7 + H2SO4 + 5H2O = Na2SO4 + 4H3BO3.

Boric acid crystallizes from water in white nacreous laminae belonging to the triclinic system; it is difficultly soluble in cold water, but dissolves readily in hot water. It is one of the “weak” acids, its dissociation constant being only 0.08169 (J. Walker, Jour. of Chem. Soc., 1900, lxxvii. 5), and consequently its salts are appreciably hydrolysed in aqueous solution. The free acid turns blue litmus to a claret colour. Its action upon turmeric is characteristic; a turmeric paper moistened with a solution of boric acid turns brown, the colour becoming much darker as the paper dries; while the addition of sodium or potassium hydroxide turns it almost black. Boric acid is easily soluble in alcohol, and if the vapour of the solution be inflamed it burns with a characteristic vivid green colour. The acid on being heated to 100° C. loses water and is converted into metaboric acid, HBO3; at 140° C., pyroboric acid, H2B4O7, is produced; at still higher temperatures, boron trioxide is formed. The salts of the normal or orthoboric acid in all probability do not exist; metaboric acid, however, forms several well-defined salts which are readily converted, even by carbon dioxide, into salts of pyroboric acid. That orthoboric acid is a tribasic acid is shown by the formation of ethyl orthoborate on esterification, the vapour density of which corresponds to the molecular formula B(OC2H5)3; the molecular formula of the acid must consequently be B(OH)3 or H3BO3. The metallic borates are generally obtained in the hydrated condition, and with the exception of those of the alkali metals, are insoluble in water. The most important of the borates is sodium pyroborate or (q.v.).

Borax and boracic acid are feeble but useful antiseptics. Hence they may be used to preserve food-substances, such as milk and butter (see ). In medicine boracic acid is used in solution to relieve itching, but its chief use is as a mild antiseptic to impregnate lint or cotton-wool. Recent work has shown it is too feeble to be relied upon alone, but where really efficient antiseptics, such as mercuric chloride and iodide, and carbolic acid, have been already employed, boracic acid (which, unlike these, is non-poisonous and non-irritant) may legitimately be used to maintain the aseptic or non-bacterial condition which they have obtained. Borax taken internally is of some value in irritability of the bladder, but as a urinary antiseptic it is now surpassed by several recently introduced drugs, such as urotropine.

BORING. The operations of deep boring are resorted to for ascertaining the nature, thickness and extent of the various