IIKII K I' FLORESCENCE 



188'J, an<l 'tis in 1898, and of that largo quantity only 25,000 tonx \\,,r.- 



.\pnried, tin- lialance IMMII^ used up in tlio exceedingly important I ;.-nn,ui 

 chemical indust i-ii's which within the past t hreo ijiiurtorri of u rontury have 



.mled I'rniii boiii^r nominal to u valuation of <i.,n.ooo,oou. 'I ho imp* 

 Hulphuric acid taki-n l>y India have uvoragod from l!02 7 Us. <i,f>H, IKS in 

 \ .due. 



bhe liiKT sorts of glass, ami i'r many other minor purposes, a KKFLNED 

 required. This is obtained by re-dissolving the ash in hot 

 . settling, boiling down and re-furnacing the result being a purer 

 Duality oi c.irl'onato. SODA CRYSTALS may be said to be a woll-knoun .-,). .j.il 

 preparation that contains 10 parts of water in comliiiiation with tho carbonate. 

 For household purposes of cleaning, bleaching, etc., soda crystals are ntill sold. 

 Tin- other substances obtained from sodium carbonate that muy bo h. ic men- 

 ti"Mfd are the bicarbonate of soda and caustic soda. Meloro proceeding to deal 

 uith tho hist mentioned, the Indian manufacture and sources of supply of car- 

 lionate of soda nmy be dealt with very briefly. Those have already been in- 

 cidentally mentioned, namely, Reh and Barilla, but to the former must be added 

 tin- sources of natural carbonate derived from the waters of certain lakes, such 

 as tho Lonar in Berar. [Cf. Oldham, Man. Econ. Geol. 2nd., 19.] 



5. Reh OP Sajji-matti ; Ironside, Phil. Trans., 1774, Ixiv., (eel. xiii.), 

 '><>',; Sleeman, Tour through Oudh, 1858; Agri. Ledg., 1893, Nos. IL' 

 1:5; 1896, Nos. 1, 33; 1897, Nos. 5, 7, 13; 1901, Nos. 4, 13; 1902, 

 No. 5, 117-24 ; Oldham, Man. Econ. Geol. Ind., 1893, 447 ; Mollison, 

 Textbook Ind. Agri., i., 77-80 ; Wedderburn, Drought-resisting Fodder 

 Plants, in Ind. Famine Union Leaflet, Dec. 1901, No. 2 ; Jan. 1903, No. 8 ; 

 Alkali Land and its Reclam., in Dept. Land Rec. and Agri. Mad., 1905. 



This is an efflorescence that occurs on the surface of the ground, in most 

 provinces of India. It may be said to be a mixture of the following salts : 

 sodium carbonate (sajji), sodium sulphate (khari), and sodium chloride (com- 

 mon salt or namak). In most localities the carbonate predominates but in 

 others the sulphate, and in the latter case it is very often associated with 

 potassium nitrate or even with, calcium nitrate. Soils badly impregnated 

 with soluble alkali salts are variously designated as usar, bhddi, refidl, 

 rehdr, reh, kalar (kalr), etc., though these terms are employed occasionally 

 to denote the presence of common salt, just as khdri usually indicates a 

 soil containing the sulphate. But it may be here remarked that the earlier 

 investigators of usar lands speak of the sulphate as being the most abun- 

 dant constituent. Hence apparently Yule and Burnell (Hobson-Jobstm, 

 (llosx. of .hii/lo-Ind: Words) defines reh as an efflorescent sulphate of soda 

 mixed with chloride and occasionally carbonate. On the other hand, 

 \ orlcker advanced what is to-day the correct view (Improv. Ind. Agri., 37) 

 when he said of reh, " The salts are principally impure carbonate of soda, 

 I nit sulphate of soda also occurs largely and with them are found common 

 salt and salts of lime and magnesia." An efflorescence of the nitrates of 

 potash or soda would oftener be viewed as of value rather than of danger. 



Reh frequently occurs in such abundance as to give origin to large tracts 

 of desert and constantly increasing tracts the surface being literally 

 encrusted with a white, snow-like deposit (hence the name reh or rej 



shining) or the salt may be invisible and only present to an extent 

 to greatly lower fertility, or while still hardly visible, may yet 

 the soil more or less sterile for at least half the year. In passing 

 it may be added that fuller's-earth is a hydrous silicate of alumina, but 

 i.s often called, though ineonvetly, sajji-matti : it contains no soda. 



Formation of Usar. The opinions advanced regarding alkali deposits vary in 

 consequence of what might bo called professional bias. Apparently the earliest 

 mention of such deposits is made l>y Sleeman. His theory is in eSSenj i.-d -.not tar 



51 



ALKALIS 

 REH 



Sulphuric Artil. 



TleflnoJ Soda. 

 SoJaCryaUb. 



Bicarbonate. 

 Indian Supply. 



D.E.P., 

 vi., pt. i. 

 400-27. 

 Reh. 



Soil- 

 impregnation. 



Names. 



Composition. 



Sterility of Soil. 



Formation of 

 Uaar. 



