IRON 



ORES 



SWEET POTATO 



Yield. 



Alcohol. 



D.E.P., 

 iv., 499- 

 524. 

 Iron. 



Ores. 



to 3 inches deep, while the other node is left free. The cuttings are 

 usually placed along ridges, though sometimes in flat beds. The ridges are 

 about 18 inches apart and the cuttings are deposited one foot apart 

 on each side of the ridge, half-way between the crest and the bottom of the 

 furrow. Cross furrows are also drawn which form channels for irrigation. 

 Weeding should be attended to and the crop watered every eight or twelve 

 days. Care must also be taken to prevent the plants rooting at the nodes, 

 for otherwise small tubers of no value will be formed at the points of 

 attachment and these will deduct from the growth of the large tubers at 

 the main root. 



Yield. If planted in October-November the crop should be ripe in 

 April and the tubers lifted at once, else much damage will be done by 

 rats and white ants. The vines or haubus are reaped before the tubers 

 are dug. A good crop may yield six tons per acre, worth about Rs. 300. 

 The cost of cultivation in the Surat district Mollison gives as Rs. 134. 



Sugar and Alcohol. The sweet potato contains more dry starchy 

 and sugary matter than the ordinary potato, but less nitrogenous substance. 

 Analysis shows it to possess about 10 to 20 per cent, of sugar and about 

 16'05 per cent, of starch. It is said to be an excellent source of alcohol, 

 100 kilos of tubers yielding about 12 to 13 litres of absolute alcohol. 



Recently it has been largely cultivated in some parts of the world as a 

 source of sugar. By the Natives of India it is commonly used as food, 

 either cooked in curry or boiled, roasted or fried. 



\Cf. Piso, De Med. Brazil, 1648, 94 ; Hernandez, Nova PI. Hist., 1651, 299 ; 

 Forster, PI. Esc., 1786, 55-6 ; Bentham, Rev. of Targioni-Tozzetti, in Journ. 

 Hort. Soc., 1855, ix., 141-2 ; De Candolle, Orig. Cult. Plants, 1884, 57-8 ; Basu, 

 Agri. Lohardaga, 1890, pt. i., 78 ; Nicholls, I.e. 288-90 ; Duggar, Sweet Potato 

 Cult., etc., U.S. Dept. Agri. Bull., 1895, No. 26 ; Thorpe, Diet. Appl. Chem., 1898, 

 i., 292 ; Woodrow, Gard. in Ind., 1899, 391 ; Der Tropenpflanzer, 1902, vi., 285- 

 96 ; Mollison, Amer. Sweet Potatos for Ind., in Ind. Planting and Gard., Oct. 30, 

 1902 ; Sweet Potato Sugar in Formosa, Aug. 1, 1903 ; West Ind. Bull., 1901, ii., 

 No. 4, 293-302 ; 1902, iii., No. 3, 206-11 ; v., No. 1, 5-6, 25-6, No. 3, 281-6 ; 

 Firminger, Man. Gard. Ind. (ed. Cameron), 1904, 478.] 



IRON AND IRON MANUFACTURES. Ball, Man. Econ. 

 Geol. Ind., iii., 335-420 ; W^att, Rev. Min. Prod. Ind., 1894-7 ; Mahon, 

 Rept. Manuf. of Iron and Steel in India, 1899 ; Holland, Rev. Min. Prod. 

 Ind., 1898-1903, 11-2, 51-2. 



PRODUCTION. Iron is commonly said to exist in nature in two great 

 classes of workable ORE (1) Carbonates and clay ironstone, and (2) 

 Oxides, like hematite and magnetite. The CARBONATES consist essen- 

 tially of two kinds : (a) those in which the salt is crystalline and little 

 admixed with earthy matter, and (6) those in which a larger or smaller 

 amount of clay is intimately intermixed with the ferrous carbonate. The 

 former is spathic iron ore and the latter argillaceous ore or clay ironstone. 

 Clay ironstone exists in large deposits in many coal measures and is then 

 known as black-band. The OXIDES may be spoken of as of three kinds 

 (a) anhydrous ferric oxide ; (b) hydrated ferric oxide ; and (c) a mixture 

 of ferrous and ferric oxides such as the magnetic oxide of iron. Hughes 

 Buller has recently sent from Baluchistan a natural mineral known as 

 khaghal or lagh, which is employed as a dye. This has been ascertained 

 to be an impure sulphate of iron. " The most abundant iron ores are 

 the minerals magnetite and hematite which occur in numerous places 

 with quartz, making quartz iron-ore schists which are generally members 



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