6/^6 



THE TROPICAL AGRICULTURIST. [April i, 1887. 



nitrate present may be converted into potassium 

 nitrate, the nitric acid in the calcium nitrate ex- 

 changing bases with the carbonic acid united to 

 the potash in the wood ahhes. The very weak 

 nitrous solution thus obtained is used instead of 

 fresh water for washing through the contents of 

 another series of pots, and thus becomes grauually 

 charged with saltpetre to the extent of 2 or 3 per 

 cent. The next process is the removal of the 

 water and crystallisation of the salt. This is con- 

 ducted in elliptical iron dishes, measuring cue or 

 two feet across and si.x to nine inches deep, heated 

 from beneath ; as evaportation proceeds, frcsh liquor 

 is added, during a period of twelve to eighteen hours. 

 The scum which rises is skimmed off, and at a certain 

 point of concentration the crude potassium nitrate, 

 with accompanying saline impurities, is abundantly 

 precipifated. This product in some districts is termed 

 dhouah, and contains 45 to 70 per cent of potassium 

 nitrate. The small pans used in the Upper Punjaub 

 give 8 to 16 lb. of crude nitre per shift of thirty to 

 thirty-six hours. Over 4,000 pans are kept working in 

 the Punjaub, paying an anuual tax of two rupees. In 

 addition, there are over a dozen large shallow basins, 

 called agar, where sun-heat is utilised for evapor- 

 ation ; these jsay eight rupees yearly. 



In the different districts, slight modifications of 

 the process described above are in vogue. Thus, in 

 Mooltan, the liquor, after twenty to twenty-four 

 hours boiling, is often run into a vat to cool for a 

 night, and next morning the crystals are raked out 

 and washed in a woollen cloth, being then tied up in 

 it, and exposed to the sun till the moisture has been 

 dissipated. Sometimes the filter is made on the 

 ground in an inclined situation being formed with 

 mud walls lined with stiff" clay on three sides, the 

 remaining sides being left open for escape of the 

 liquid, but provided with reeds or closely-woven 

 grass mats, with or without a bamboo false bottom ; 

 the liquid passes into a reservoir made of pucka 

 musonry. In Guzerat, the nitrous solution is passed 

 through a cloth filter ; it is evaporated to about one- 

 fourth its bulk, and on cooling affords an impure 

 crystalline product {dhouah) worth about three rupees 

 per maund (say, 8s. per cwt.). When re-dissolved, 

 filtered, and re-crystallised, forming kahnee, it is worth 

 eight rupees per maund. The following table of the 

 average cost per ton of Indian saltpetre is instruc- 

 tive: — 



£ s. d. 

 Prime cost of crude material at the factory 4 2 



Salaries, bigs, packing, &c ,!. 1 14 2 



Freights and expenses from factory to 



Bombay 5 17 3 



Interest on outlay at 9 per cent 13 8 



Government license 2 7 



Insurance at 7 per cent 17 1 



Profit per ton 



13 6 

 1 0. 



Selling price at a brisk demand at Bombay £14 7 

 Indian exports of saltpetre reach something like 

 25,000 tons annuallj', with a value of over half a 

 million sterling. 



Ceylon. — The nitrates of j^otash and lime are of 

 frequent occurrence in Ceylon. Some thirty places 

 might be enumerated where saltpetre is produced and 

 has been prepared fwr market. The formation of the 

 mineral is apparently confined to caves in dolomitic 

 rocks, the felspar iu which contributes the potash 

 base. The caves are generally remote from inhabited 

 places, being situated in desolate and not easily 

 accessible regions. Future explorations in the in- 

 terior will probably add to the number already known. 

 While some of the caves are the resort of vast 

 numbers of bats, whose dung accumulate.s in them, 

 others are quite untenanted. 



An analysis of the most productive nitre rock near 

 Doouibera, iu an unfrequented cave, showed 2 4 per 

 cent potassium nitrate, and 0'7 per cent of mag- 

 nesium nitrate- The nitre earth from the great cave 

 in Lower Ouva, ne^r Wellaway, yields 35 per cent 



of calcium nitrate, and 33 of potassium nitrate. The 

 nitre crop is harvested during six months of the year 

 by chipping off the incrusted portions of the walls of 

 the caverns ; the fragments are reduced to powder, 

 mixed with an equal portion of wood ashes, and 

 dosed with water. The potas.sium nitrate present, 

 as well as that produced from other nitrates by the 

 action of the wood ashes, is dissolved by the water, 

 and the solution is evaporated first in pits e.'cposed 

 to the sun's rays, and then to the crystallising point 

 in fire-heated pans. 



Burma. — Some of the caves contain accumulations 

 of nitrous earth, and the preparation of the salt is 

 carried on extensively between Pugan and Ava, on 

 the Irawadi. 



Thibet. — In the government of Rudokh, saltpetre is 

 obtained . by digging up the soil, which is put into brass 

 vessels, and treated with hot water. The solution thus 

 formed is decanted into another vessel, and there allowed 

 to cool, that the nitre may crystallise out. By the 

 crude native method, no man can prepare a sheep load 

 (say 20 lb.) in three weeks. 



Sumatra. — The nitre caves in the county of Caltown, 

 near the land of the Duni river, are filled with nests of 

 innumerable birds of the swallow kind, which abound 

 the more the further the caves are penetrated. It is 

 their dung, forming a deposit in many places 4 to 15 

 feet thick, which forms the saltpetre. A cubic foot of 

 this earth, on boiling, will afford something like 8 lb. 

 of nitre. — Journal of the Society of Arts. 



AGEICULTURE IN JAPAN. 



Field farming in Japan is unknown, the tillage 

 being realiy gardening, but of the most thorough 

 character. Oonsul-General Van Buren says that 

 fully one-half of the population are farmers, and of 

 the day labourer or coolie class a large number is 

 employed iu the cultivation of the .soil. The average 

 size of the garden farms is about half an acre. The 

 fee simple of the soil, formerly in the feudal lord, is 

 now held bj' the farmer. The area under cultivation 

 has been extended fully one-fifth within the past ten 

 years. The Japanese Archipelago extends north and 

 south through fifteen degrees of latitude, and the 

 cultivated areas are at all altitudes, from the sea level 

 to 10,000 feet above, with the climate of the tem- 

 jjerate or sub-tropical zones. Of the 50,000,000 

 acres of tillable land, a little less than one-fourth, or 

 about 12,000,000 acres, are under cultivation. This 

 is owing to the absence of good roads and proper 

 means of tran.»portation ; most of the carrying in 

 the farming districts is done upon the backs ot 

 men and animals. Kice is the staple product of 

 the country, growing in all districts of the empire ; 

 about 6,800,000 acres, or more than half of all the 

 area under tillage, is, during the summer, devoted 

 to it3 cultivation. Wheat is grown in all parts of 

 the empire, and it is estimated that the yield averages 

 twenty bushels to the acre. It is mostly eaten in the 

 form of cakes, cooked without any process of fer- 

 mentation. The wheat flour is ground in a small 

 stone mill, and is bolted by hand in a small box 

 about two feet wide and three feet long. The up- 

 lands are preferred for wheat growing, and the soil 

 is thoroughly dug up and pulverised with a long 

 bladed mattock. It is then divided into small plots, 

 each of which is then furrowed by the same instru- 

 ment into rows, three or four inches deep and twelve 

 or fifteen inches apart. Into these furrows, ashes 

 and a thoroughly decomposed compost is scattered, 

 and in October, seed is dropped by hand, about 

 one to one bushel and a quarter to the acre, and 

 covered by the mattock to the depth of about one 

 inch and a half. The ground is turned up two or 

 three limes a month, and liquid manure is applied 

 three or four times during the winter and spring to 

 the roots. In the autumn some hirdy vegetables are 

 planted between the rows of wheat. The wheat 

 ripens in May, and is cut by a knife and bound into 

 small bundles, which are either hung up on tree3 or 

 bamboo poles, or laid on hard ground to dry, when it 

 is carried to the farmhouse, where it is tUraslied. 



