NITRATES OF 



POTASH AND SODA. 



of any manure producing this rapid, darkly- 

 green, luxuriant growth, from which nitrogen 

 is absent. Saltpetre is naturally generated on 

 the earth's surface under favourable circum- 

 stances, and in situations much more frequent 

 than the farmer is wont to suspect. Wherever 

 Ammonia is copiously generated, as in stables, 

 farm-yards, &c., and wherever the nitrogen, 

 which forms a component portion of ammonia, 

 at the moment of its extrication has access to 

 potash or calcareous matter, there saltpetre is 

 usually formed. This is naturally done so 

 copiously, in some of those situations in which 

 the farmer is placed, as to form fine crystalline 

 exudations on the walls ; and it is in such 

 places that those plants which abound in salt- 

 petre, as the nettle, the horse-radish, &c., com- 

 monly flourish with uncommon luxuriance. It 

 has been proved by those who gather the salt- 

 petre from the earth's surface in southern 

 Africa and Hindostan, as well as by those who 

 prepare the artificial saltpetre beds in Spain 

 from the sweepings of the streets of Madrid, 

 that nothing more is requisite for the forma- 

 tion of saltpetre in these beds of earth, than the 

 presence of a certain proportion of decompos- 

 ing animal and vegetable matters, with some 

 potash, and calcareous matter. Now all these 

 essentials for the formation of saltpetre must 

 in many situations be afforded by the farmer's 

 own soils. There are, in fact, many lands in 

 the cultivator's possession where, especially 

 in dry summers, the formation of saltpetre in 

 minute proportions is continually taking place ; 

 where the putrefaction of animal matters must 

 in small proportions be productive of ammo- 

 nia; and where an abundance of potash is al- 

 ready existing in the soil to neutralize the 

 nitric acid produced, and form with it nitrate 

 of potash or saltpetre. For it has been ascer- 

 tained that if, at the moment when nitrogen is 

 evolved, it is presented with oxygen gas, that it 

 combines with it, and forms nitric acid. Here, 

 then, we have explained to us the origin of the 

 acid of the nitre, and we know that its base, or 

 potash, is to be found in some form or other in 

 all cultivated soils. And if we admit that this 

 must in some instances be the case, then we 

 shall be furnished with a ready explanation of 

 many of the difficulties and discordant results 

 which have attended the recent very general 

 application of these two nitrates, since the fact 

 that saltpetre has commonly been found to 

 produce the least results upon those deep, rich, 

 alluvial soils which must abound in decom- 

 posing organic matters, in some degree coun- 

 tenances the conclusion, as does the smallness 

 of the quantity of saltpetre applied ; for, if once 

 we concede the possibility of the soil, under 

 favourable circumstances, being able to gene- 

 rate this salt, then it will be allowed that one 

 cwt. per acre is not a large crop for the soil to 

 produce. That in this way it is generated in 

 some of the richest soils of the East, to such 

 an extent as to cover the surface with a white 

 incrustation, is known to every oriental tra- 

 veller. To a still greater extent is the land 

 in those countries impregnated in many situa- 

 tions with the nitrate of lime, a salt which, 

 possessing the same acid as nitre and cubic 

 nitre, has lime instead of potash or soda for 

 840 



1 its base \ and from some experiments Which I 

 have made, I have little doubt but this nitrate, 

 which is of much less cost than either the ni- 

 trates of potash or soda, will be found a valu- 

 able agent for the use of the cultivator. For 

 its excessive deliquescent or moistening pro- 

 perties, which render it so unmanageable for 

 many manufacturing purposes, make it more 

 valuable to 'the cultivator of the poor, dry, 

 thirsty soils, where artificial fertilizers are 

 most in request. If nitrate of lime was import- 

 ed at a reasonable rate, the farmer could rea- 

 dily, if he wished, make his own cubic petre, 

 at a very low price, by mixing the nitrate of 

 lime with glauber salts (sulphate of soda), by 

 which means a rapid decomposition takes 

 place, the result of which is nitrate of soda 

 (cubic petre) and sulphate of lime (gypsum). 

 The inferior, impure, refuse glauber salts, made 

 by the cotton bleachers in the preparation of 

 their bleaching powder, would answer for this 

 purpose very well. 



My experience of the enriching powers of 

 saltpetre extends over several years. My ear- 

 liest experiments were made in the kitchen 

 and flower garden, in which I found very con- 

 siderable advantage in increasing the beauty 

 and in prolonging the bloom of several of the 

 tenants of the latter; and in the former I found 

 excellent results from applying it at the rate 

 of 2 cwt. per acre to my beds of horse-radish, 

 and in very small proportions, as one-eighth 

 of an ounce per gallon, to the water with which 

 I watered, to prevent mildew, &c., my early 

 and late crops of pease, wall-fruit trees, &c. 

 My experience with it as a field crop has been 

 principally confined to the gravels of Essex 

 and the chalks of Hampshire and Berkshire, 

 in which, especially upon grass, I have ob- 

 tained results exceedingly satisfactory. In 

 1840, 1 tried it upon the old clay grass soils 

 of Knitbury, in Berkshire, with various other 

 manures; 1st, at the rate of 1 cwt. per acre; 

 2d, nitrate of soda, 1J cwt. per acre ; 3d, Poit- 

 tevin's manure, 14 bushels per acre; 4th, gyp- 

 sum, 1 cwt. per acre; 5th, nitrate of soda, 



cwt., and gypsum 1 cwt. per acre. These 

 were all applied by hand in the month of April; 

 but although they all produced a better crop 

 than the soil simple, yet the extreme dryness 

 of the season operated very materially against 

 the success of almost all artificial dressings, 

 and the produce of the whole plot was much 

 below an average crop. Nos. 1, 4, and 5 were 

 decidedly the best, producing at the rate of 

 rather more than 2 tons of hay per acre; Avhile 

 the produce of the soil simple was less than 

 22 cwt. per acre. The grasses were of the 

 ordinary kinds tenanting the upland pastures, 

 mixed with a considerable portion of nearly 

 worn-out roots of lucern, which, in the plot 

 No. 4, gypsum alone, and in No. 5, gypsum 

 and cubic petre mixed, was revived by the ap- 

 plication to a very remarkable degree; its 

 plants nearly doubling in height any other por- 

 tion of the land, 



In some experiments, at which I was pre- 

 sent, on the barley and wheat land of the chalk 

 formation in the neighbourhood of Winchester, 

 the effect of the saltpetre was excellent; the 

 green colour of the crops was rendered much. 



