April I, 188;,] THE TROPICAL AGRICULTURIST/ 



645 



depeacl the health and vigour of the plant with its 

 long succulent stem and succession ot long broad 

 leaves ; it should, therefore, be placed in ihe best 

 possible condition to enable it effectually to meet the 

 heavy demand on it. 



By the native method the root is on or near the 

 surtace of the ground. The hold gets 12 oi- 14 surface 

 ploughiugs giving a seed bed only lour or five inches 

 deep. Tne little manure (if any is given) is scattered 

 irregularly over the surtace, a plough goes ruuud tUe 

 fiekl in a continually decreasing u.rcle, and the cuttings 

 are drojjped iuto the shallow track so made. Tnere 

 may be a little manure wbere they fall, or there may 

 not be any. The cuttings are covered wiih about tUiee 

 inches of earth by a piece of wood drawn over the 

 surface, a man or two standing ou it, eacn .supporting 

 hiciiself by holding the tail of the buliock in front 

 of him. This surtace covering soon dries ; the surface 

 is then louseueJ a little by the hoe, tlie loots being 

 carefully avoided. A little manure may now be placed 

 round each plant by hand, and water is let on 

 till the field is sumberged or water-logged, thus sealing 

 up the roots from air in plastic clay or isam compressed 

 by the downward couise of the water, and hardening 

 as it dries. As ttie hoe avoids the roots, the compression 

 of the soil around thera increases just wUeie it 

 should be most friable. The hoein_ is repeated about 

 three times, followed by a melwanee wateriug, that is, 

 till the ground is water-logged each lime. When the 

 plants reach a certain height, and the leaves begin 

 to shade the field, hoeing is stopped, and as they 

 grow, being close together with no regularity, a thick 

 jungle is the result excluding sun and tree circulation 

 of air. Considering the nature of the plant and the 

 work its root has to do, this treatment of it is most 

 irrational 



In Mauritius, West Indies, and other places where 

 cane cultivation is under European supervision, the 

 cuttings or seedlings are laid at least nine inches 

 under the surface of the ground, either in careluUy- 

 made rectangular oblong holes in rows three and-a-half 

 or four feet apart, or in continuous channels or furrows 

 made by hoe; or double mould board plough, the 

 bottom being flat, and eight or nine inches wide, 

 that is, wide enough to receive three cuttings placed 

 some distance from each other. A field planted in 

 this way will take as many cuttings as are usuallj' 

 put in by the native method. Tbe space between ttie 

 rows need not be ploughed, only cleaned of weeds 

 by hoe, these are left on the ground, and are covered 

 by the earth from the channels or holes. 



Previous to planting the cuttings, manure in proper 



quantity is spread over the bottom of the channels 



and mixed with a little earth. On, or in this, the 



cuttings are laid end to end either in single, double, 



or triple rows as the width of the bottom may allow, 



and covered by hand with about three inches ot 



earth. The "hole" system is used in Mauritius, the 



ground is hilly and undulating, rain is frequei^t, and 



each hole retains what may fall into it. In India 



where irrigation is necessary, the channel or deep 



furrow metliod is best. After some days the surface 



of the soil in the bottom of the channels is loosened 



by hand. This may be done by women or children, 



whereas the hoeiug of the rioc's field has to be done 



by men. If water is now necessary, a little is allowed 



to flo.v from one end of the channel to the other, 



and then shut off. As the plants rise, more earth 



is filled in around them with a little manure where 



it may be needed ; the loosening of the surtace, watering 



and filling in is repeated till the channel is filled ; 



after which, as the plants grow, the earth is drawn 



from the spaces between the rows and heaped round 



the roots till a ridge is formed at least nine inches 



high over the original surface. Subsequent irrigation 



is given in the hollows between the ridges, the water 



not being allowed to reach the top of the ridges by 



four or five inches, which are thus left friable, and 



open for the action of the air and expansion of the 



roots. 



Our ryots have for years seen and acknowledge the 

 considerable economy of labour, wat«r, and manure in 

 this method as compared with their own. They have 



al>o seen the commou mongoo cane in the district so 

 improved that tUey tiad to oe assured it was norhing 

 else, yet none of them have htd the enterprise to 

 adopt it, th jugh several among tuem have been at work 

 on the cane fields of tbe West Indies and Mauritius, and 

 know the method aud its results. 



Cane culture should be more of the nature of garden 

 than field cultivation, aud if doutj with a resoaible 

 coQbideratiou of the nature aud necessities of the 

 plant, a third of tbe laud, uow yearly devoied to cane, 

 could be put under other crops with no falling off m 

 the weight of sugar produced. 



The iudu-.try, as a who e, aud in its details, from the 

 preparation ot tne laud till tUo crude produce is ready 

 for the market, IS iu iivery uackvvar>l and wasteful cou- 

 tlitiou ; th-^re is no reasou except tue inertia of the ryot 

 why this shouid be sj. This might be uveicome, and a 

 better rut op^netl out by .some sustained effort on ttie 

 part 01 Governuienc, probaoiy a gra mated set of prizes 

 lor tbe best caue fields cuitiv ited wita refei euce t J tne 

 nature and requirements of tne piant. We k.iow by. 

 experience tuey under.stand wUat this meaus when ex- 

 plained tj them terms witli winch they are familiar. 

 — Indian Ayricidtarist. 



SOURCES OF SALTPETRE. 



BY C. G. WAENFOBU LOCK. 



Whilst evtry miner is aitraciei by mineral veins 

 which prooiise to yield metals, the majority over- 

 look a class of earthy products which, nevertheless, 

 pos.sess consideraole commercial value. Foremost 

 amongst these is saltpetre, or potassium nitrate. The 

 following notes on this itseful salt have been collected 

 by the writer at various times, and in various localities, 

 and will probably be intert sting to many readers of 

 the Journal, as accessible iuiormatioii on the subject 

 is not abuudaut, aud ^ome of the deposits alluded to, 

 seem worthy ot better development. The generally 

 accepted conditions necessary for the formation of 

 Saltpetre are (1) the presence of decaying organic 

 matter, whose decomposition affords a supply of 

 nitrogen; (i!) accessor atmosperic air to oxidiae the 

 nitrogen into nitiic acid ; (3) sutticient potash in aa avail- 

 able form (such as wood ashes or decomposed felspathic 

 rocks) for the nitric acid to combine with as fast as it is 

 liberated. (Jiven these conditions, the formation of 

 the salt will take place in very varieu situations, being 

 most commonly observed in countries where a tropical 

 climate favours the decomposition of organic matters. 



With this introduction, we may proceed to indicate 

 the chief localities ot production. 



India. — Some saltpetre is obtained from the slimy 

 mud deposited by the Eiver Gauges during the flood 

 season. Analysis of a nitrous earth from Tirhut, in 

 Bengal, gave 83 per cent of potassium nitrate, and 

 '61 of calcium nitrate, or 12 per cent of total nitrates. 

 The soil around old buildings iu the Punjaub is very 

 productive ot nitre, which appears as an effljresceiice, 

 not to be confouuued with the sodium suiphate crust 

 occurring on the 1 eh, or barren lands. The depjsit is 

 scraped up as often as it is renewed, aud submitted 

 to simple treatment for the separation of the nitre 

 from ttie accompanying dirt by the agency of water 

 and filtration. A small spade is used in collecting the 

 earth, which is taken off to a depth of one or two inches, 

 and pded in heaps two to four feet high, where it is left 

 without taking harm till an opportunity arises for 

 trau-poriing it to a spot where water and fuel are 

 available. In the upper part of the Punjaub, the 

 extraction process is conducted m a series of wide- 

 mouthed earthen pots, with an aperture iu the 

 base, supported ou earthenware stands, so as to 

 admit of placing cups beneath the pots. On 

 the bottom of each pot is spread a bed of straw, 

 covered with a layer of wood ashes; above this, the 

 nitrous earth is .idded till it reaches nearly to 

 the top of the pot. Then water is applied till all 

 soluble salts contained in the earth have been dissolved 

 and carried in solutions into the cups below. The straw 

 bed acts mechanically ws a filter to hold back insoluble 

 matters; the wood ashes act chemically, affording 

 potash in ati available form, so that any calcium 



