806 L H L I
Logwood is prepared for use by dyers, &c., in the form of chips and raspings, and as a solid brittle black extract. Chipped logwood is moistened with water and spread in thin layers till a gentle fermentation sets up, whereby, under the influence of liberated ammonia, hæmatoxylin is formed from the glucoside. By exposure to the air, through repeated turnings of the mass, hæmatein is developed from the hæmatoxylin, and the chips gradually become coated with the brilliant metallic green crystals of hæmatein. Logwood extract, largely used in calico printing, is obtained from oxidized chips and raspings by lixiviation, the solution being concentrated at as low a temperature as possible.
The principal use of logwood is for dyeing wool and
woollen goods, on which it produces, with various mordants,
shades of blue from a light lavender to a dense blue-black,
according to the amount of logwood used. It is more
employed in combination with other dye-stuffs than as the
sole tinctorial agent, the best and most permanent blacks
on wool, known as woaded blacks, being first dyed blue in
the indigo vat, and finished black with logwood and
bichromate of potash. In calico-printing logwood is used
to produce steam purples, for the production of which the
calico is mordanted with stannate of soda, and printed with
a strong solution of logwood extract thickened with starch.
By steaming, the hæmatein of the logwood combines with
binoxide of tin precipitated in the fibre, and thus develops
a bright purple colour. Logwood blacks, which are a
standard product of print works, are produced by mordant
ing with iron liquor, passing the calico through a logwood
solution, and developing and fixing the colour by treatment
with a weak solution of bichromate of potash. Logwood
blacks assume a bright red tint by the action of dilute
acids, a test by which they can readily be distinguished
from aniline and other fast blacks. Logwood is also largely
used in the preparation of INK (q.v.~), and to a small extent
in medicine. The imports of logwood into the United
Kingdom during the year 1880 amounted to 69,280 tons,
the estimated value of which was £192,392.
LOHÁRDAGÁ, or Lohardugga, a district in the lieu tenant-governorship of Bengal, India, between 22 20 and 24 39 N. lat. and 83 22 and 85 56 E. long., is bounded on the N. by Hazáribágh and Gayá, on the N.W. and W. by Mírzápur district and Sargújá and Jashpur states, and on the S.E. and E. by Sinhbhúm and Manbhúm districts. It comprises Chutiá Nágpur proper, and the Palámau subdivision. Chutiá Nágpur is an ele- vated table-land, forming the central and south-eastern portion of Lohárdagá district; its surface is undulating, and the slopes of the depressions lying between the ridges are cut into terraces covered with rice. Palámau, which forms the north-western portion of the district, consists on the east and south of spurs thrown off from the plateaus of Hazáribágh and Chutiá Nágpur, while the remainder of the tract is a tangled mass of isolated peaks and long irregular stretches of broken hills. The average elevation of Palámau is about 1200 feet above sea-level, but some peaks rise to over 3000 feet. This part of the district contains no level areas of any extent, except the valleys of the North Koel and Amánat rivers, to which rice cul tivation is confined. The principal rivers of Lohárdagá are the Subarnarekhá and the North and South Koel. The entire district was probably at one time overgrown with dense forest, but the forest area has been continually dwindling, owing to the spread of cultivation and the practice of girdling the sál trees for resin.
The census of 1872 disclosed a total population of 1,237,123 (621,548 males and 615,575 females), spread over an area of 12,044 square miles; of these only 91 were returned as Europeans and 3 as of mixed race. The aboriginal element is very strongly represented – the Mundas numbering 163,051; Kols, 132,104; and Uráons, 151,810. The most numerous among the semi-aboriginal tribes are – the Bhuíyás, 45,008; Kharwárs, 33,573; Bhogtas, 33,452; and Dosádhs, 25,223. The Hindus number 741,952, and Mohammedans 58,211. The Christian population is larger than in any other Bengal district, except the metropolitan one of the Twenty-four Parganás. In 1872 the total Christian population numbered 12,781, of whom 12,687 were natives, nearly all belonging to the aboriginal tribes of Mundas and Uráons. Most of them are poor, but they possess considerable influence, and are rising in public esteem. The two missions are the German Lutheran and Church of England, which successfully work together side by side. The population is entirely rural, Ranchí town (12,086) being the only place with more than 5000 inhabitants. Rice forms the staple crop; other crops are wheat, barley, Indian corn, millets, peas, gram, oilseeds, pán, cotton, and tobacco. Opium cultivation was introduced in 1869, and in 1874-75 yielded 245 cwts. There are two small tea plantations. Mildew and blights occasionally attack the crops; droughts seldom affect any considerable area. The principal trading place is Garwá in Palámau. Stick lac, resin, catechu, silk cocoons, hides, oil-seeds, ghí, cotton, and iron are here collected for exportation; while rice and other food grains, brass vessels, piece goods, blankets, broadcloth, silk, salt, tobacco, spices, drugs, and beads are brought to market for local consumption. The manufactures consist of shell-lac, inferior articles of brass and iron work, coarse cloth, blankets, mats, baskets, rope, and rude pottery. Iron, lime, and soapstone are worked in small quantities; gold is washed by the poorer classes from the sands of the rivers. An important coal-bearing tract, known as the Daltonganj coal-field, covers an area of nearly 200 square miles, and lies partly in the valley of the Koel river, and partly in that of the Amánat. The net revenue of the district in 1870-71 was £29,900, and the expenditure £22,563. The schools in 1876-77 numbered 303, with 8088 pupils. The climate of the table-land of Chutiá Nágpur is said to be superior to that of any other part of India, except the lower ranges of the Himálayas. The hot weather extends over almost six weeks, commencing about the 20th April, but is never really oppressive. The rainy season lasts from the middle of June to about the first week in October. The principal diseases are
malarious fever and rheumatism of a severe type.
LOIRE (Lat., Liger), the first of the rivers of France in length of course (626 miles) and extent of basin (44,979 square miles), has its headwaters in the great central plateau, and is considered to take its rise in the Gerbier de Jonc, in the department of Ardèche, at a height of 4504 feet above the sea, – though the Allier branch, which has its source about 30 miles west, in the department of Lozère, at the foot of Maure de la Gardille, 4668 feet above the sea, has an almost equal course. The two streams continue to run parallel till the upper Loire turns westward and is joined by the Allier in the neighbourhood of Nevers. All the more important affluents of the upper and middle part of the Loire – as the Cher, the Indre, the Vienne, respectively 198, 152, and 231 miles in length – have their gathering grounds in the central plateau. In the north-east the basin of the Seine comes so close (at one place to within 6 or 7 miles) that the versant towards the Loire has hardly anything to contribute; and it is not till within 65 miles of the estuary that we find an important tributary, the Maine, bringing down the drainage of the Brittany plateau. At certain seasons the Loire is navigable for ships as far as Nantes (33 miles), for boats as far as La Noirie (other 518 miles), and for rafts as far as Retournac; but for six months of the year navigation is practically impossible.
In the volume of water there is all the irregularity of a mountain
torrent; at the Bec d'Allier, for instance, – the meeting point of the
two head streams, – while the maximum current is 353,200 cubic
feet per second, the minimum is 10,600 cubic feet, and above
Orleans the range lies between 31,800 and 850. During the drought
of summer thin and feeble streams thread their way between the
sandbanks of the channel; while at other times a stupendous flood
pours down and submerges wide reaches of land. In the middle
part of its course the Loire traverses the western portion of the
undulating Paris basin, with its Tertiary marls, sands, and clays,
and the alluvium carried off from these renders its lower channel
inconstant; the rest of the drainage area is occupied by crystalline
rocks, over the hard surface of which the water, undiminished by
absorption, flows rapidly into the streams. A fall of from 3 to 4
inches over the whole river basin is sufficient to pour 35,320,000,000
cubic feet of water into the channels. When the rain is general
over the whole area, the floods on the different tributaries reach the
main river at different times; but when, through any cause, two or
more of them arrive at the same time, inundations of the most serious
character result. Attempts to control the river must have begun at
a very early date, and by the close of the Middle Ages the bed between
Orleans and Angers was enclosed by dykes 10 to 13 feet high. In
