D.E.P., 



vi., pt. ii., 

 431-47. 



Saltpetre. 



Supply. 



Conditions of 

 formation. 



Climatic 

 Conditions. 



SALTPETRE 



POTASSIUM NITKE OR SALTPETRE 



NITRATE 



SALTPETRE, NITRE OR POTASSIUM NITRATE : Ball, 

 Man. Econ. Geol. Ind., iii., 499-501 ; Watt, Agri. Ledg., 1902, No. 5, 111-4 ; 

 Holland, Rev. Min. Prod. Ind., 1898-1903, in Rec. Geol. Surv. Ind., 1905, 

 xxxii., 86-90 ; also Rev. Min. Prod. Ind., 1906, xxxvi., 81 ; Hooper, Repts. 

 Labor. Ind. Mus., 1902-3, 23-4 ; 1903-4, 37 ; also Agri. Ledg., 1905, No. 3. 

 The terra Saltpetre is used to designate nitrates found in a natural state 

 in many parts of the world, chiefly South America, Spain, Persia, Hungary 

 and India. In the last -mentioned country the salt bears the following 

 vernacular names : suriakhar, shora (sord), polti-luppu, veti-uppa, san- 

 daiva, ydnzin, etc. Shord is its Persian name Sanskritised into sordka. 



Occurrence. According to Holland, the necessary conditions for the 

 formation of saltpetre in a soil are " (1) supplies of nitrogenous organic 

 matter ; (2) climatic conditions favourable to the growth and action of 

 Winogradsky's so-called nitroso- and nitro-bacteria, converting urea and 

 ammonia successively into nitrous and nitric acids ; (3) the presence of 

 potash ; and (4) meteorological conditions suitable for the efflorescence 

 of the potassium nitrate at the surface." 



The necessary combination of characters is to be found in a marked 

 degree in various districts in the Indo-Gangetic tract, especially in the 

 Bihar section, chiefly Gaya, Tirhut, Saran and Champaran. " In this 

 part of India we have a population of over 500 per square mile, mainly 

 agricultural in occupation, and thus accompanied by a high proportion of 

 domestic animals, supplying an abundance of organic nitrogen. With a 

 mean temperature of 78 F., confined to an annual range of 68, and 

 for a large part of the year, when the air has a humidity of over 80 

 per cent., with a diurnal range not exceeding 8 above or below 84 F., 

 the conditions are unusually favourable for the growth of the so-called 

 ' nitrifying ' bacteria." 



" With a population largely using wood and cow-dung for fuel, the soil 

 around villages naturally would be well stocked with potash ; and 

 finally, with a period of continuous surface desiccation following a small 

 rainfall, the subsoil water, brought to the surface by capillary action in 

 the soil, leaves an efflorescence of salts, in which, not surprisingly, potas- 

 sium nitrate is conspicuous. Under these conditions Bihar has for many 

 years yielded some 20,000 tons of saltpetre a year " (Holland, I.e. 86-7). To 

 a less extent, commercial saltpetre is also obtained in the United Provinces 

 (e.g. Cawnpore, Ghazipur, Allahabad, Benares), the Panjab, Kashmir, 

 Central India (Bhind and Jwargarh), Bombay, Madras (Coimbatore, Salem, 

 Kistna, Vellore, Trichinopoly, Madura), and lastly Burma (Tenasserim). 



Manufacture. Hooper has furnished a concise account of this subject. 

 In preparing crude saltpetre from nitrous earth there are two distinct 

 processes (1) the leaching or exhaustion of the saline matter by allowing 

 water to percolate through the nitrous earth ; (2) the evaporation of the 

 liquor so obtained either by the sun's rays or by artificial heat. These 

 processes are carried on in Bengal by a special caste of men, the luniaJts 

 or nunias, but in parts of the United Provinces and the Panjab, ordinary 

 villagers of no special caste engage in the industry. Near Hissar, the 

 crude-nitre makers are generally low-caste kumbhars, or other Hindus or 

 Mussulmans. The nitrous earth is collected from November to the 

 commencement of the monsoon. The surface of the soil is scraped off 

 to a depth of half to one inch and the earth made into heaps or taken 

 to the factory. 



972 



Chief 

 Localities. 



Manufac- 

 ture. 



Caste Engaged.' 



