316 



THE FARMER'S MAGAZINE. 



bed, from 12,000 to 15,000 cubic feet of earth : add to 

 it rotteu dung, plants, leaves of trees, residue of grasses, 

 scrapings of houses." 



" Lay the mass on a slope, spreading over it irregu- 

 larly straw and branches of trees. Keep up a constant 

 humidity by sprinkling it with urine, dish-water, ley, 

 and the drainings of the dung-heap." 



It will be seen that the materials of an artificial nitre- 

 bed and those of compost are completely identical. In 

 the nitre-bed, the access of air is skilfully managed by a 

 system of hurdles, or by a uniform distribution of 

 faggots disposed in parallel strata. In the compost 

 heaps, the ."straw and leaves greatly favour the airing of 

 the interior of the mass, but thrown in at hazard they 

 do not always produce the effect that might be expected. 

 In a nitre-bed every precaution is taken to keep up a 

 proper humidity, which is one of the most important 

 conditions, and" at the same time the most difficult to 

 fulfil; too much humidity injures quite as much as too 

 great a dryness. In the compost, the wettings have no 

 regularity, and it may happen that the liquids do not 

 penetrate deep enough ; those channels are not formed 

 by the help of which the>ir or the water, at the will 

 of the manufacturer, flows i.ito the interior of the 

 mass. 



The nitre-bed is sheltered under a spacious shed 

 surrounded with hurdles, in order to break the violence 

 of the wind, and modify the intensity of the cold. The 

 compost, on the contrary, remains exposed to all the 

 vicissitudes of the weather, to the sun which dries the 

 surface, and the rains which draw off the soluble salts. 

 The heap of compost on a farm is most certainly an 

 artificial nitre-bed, but one badly managed, and badly 

 established, for the very simple reason that we do not 

 know that one of the elements most favourable to pro- 

 duction is saltpetre. 



There are localities where the filth is subjected to 

 nitrification before being employed as manure. In the 

 Department of the " Nord" the farmers of the environs 

 of Bergues transport in barges, to many leagues' dis- 

 tance, the gatherings and the mud purchased in the city 

 of Dunkirk, in order to mix them, in alternate layers, 

 with marl, chalk, and earth. The matters thus stratified 

 remain on the bed for two years before being taken to the 

 fields.* 



It is by forming heaps with the leaves of trees and 

 annual plants gathered from the soil after their maturity, 

 weeds hoed up whose roots have still earth attached to 

 them, that we obtain the compost for our gardens. It 

 is diflScalt to avoid the conviction that these mixtures 

 are nitre-beds. The compost, therefore, contains salt- 

 petre ; at least I have found it in those which I have 

 examined. The following is the result of many quan- 

 tities : 



Nitrates expressed in nitrate of potash in one kilogramme 

 of compost dried in the air. 



Grains. 



Compost of the farm of Bechelbronn 1.51 



Compost of leaves of Bechelbronn 5.51 



Compost of the farm Neunreiterhoff, near Haguenan. . 0.85 



Compost from a bed of a garden at Verriferes 0.94 



Compost of a kitchen-garden at Paris ..\. 1.07 



These proportions are certainly weak enough, yet 

 they are not so much below, as we might suppose, those 

 assigned to the materials manufactured at the saltpetre 

 works. According to Bauer, in the description he has 

 left us of the nitre-beds of Sweden, the saltpetre extracted 

 from one kilogramme of matter is 



From 1.65 grains to 2.20 grains for earths of ordinary 

 quality. 



From 6.00 grains to 7.00 grains for the richest earths. 



At Malta, according to Demasis, the calcareous 



* Cordier, Agriculture de la Flandre, p. 215. 



nitrified earths, after having been mixed with one-fifth 

 of wood ashes, produced per kilogramme 5.52 grains of 

 saltpetre. 



In the report of the Stewards -general of gunpowder, 

 we find that in France, in some provinces, the kilo- 

 gramme of materials naturally nitrified yield often only 

 1.20 grains of nitre; that in the most productive arti- 

 ficial nitre-beds, as that of Touraine, they extract from 

 the kilogramme of soil :* 



Grains. 



CommoDly 8.5 Nitre. 



la nitre-beds perfectly formed 10.0 „ 



Exceptionally 30.0 t » 



In the preparation of compost, nitrification is not the 

 main object, and the measures we adopt are frequently 

 very unfavourable. Thus, when local circumstances 

 allow it, we overload with urine, night-soil, blood, &c., 

 and that only a short time before the compost is spread 

 over the meadows. This is a most defective plan in 

 regard to the success of nitrification. Practice teaches 

 us that in the quantity of animal matters intermixed, 

 there is a limit which cannot be exceeded with impunity, 

 and the very conclusive experiments communicated to 

 the Academy by M. Peloaze prove that if these matters 

 predominate, not only will they be unfavourable to ni- 

 trification, but that they even destroy the nitre already 

 formed, by transforming the nitric acid into ammonia. 

 The saltpetre works, therefore, suspend the use of them 

 many months before the time fixed for the lixiviate. 

 During this last period the moistening of the earths is 

 only affected with water. 



A short time after I had presented to the Academy 

 my researches into the quantity of nitrates contained in 

 the earth and the waters, an English agriculturist of the 

 first character advis-ed the cultivators to establish arti- 

 ficial nitre-beds. I will not go so far as that. Although 

 my conviction of the utility of saltpetre in the fertiliza- 

 tion of the soil is very profound, I shall limit myself 

 to proposing that in the compounding of composts, whether 

 for the farm, the kitchen-garden, or the flower-garden, 

 we follow, so far as circumstances will permit, the pre- 

 scriptions recommended for the establishment and 

 management of a nitre-bed. For this object I have 

 placed at the end of my memoir an extract, which I shall 

 not repeat here, from the instruction, so remarkable, for 

 which we are indebted to the former stewards-general of 

 gunpowder and saltpetre. 



Let us now examine the utility of the nitrification 

 accomplished in the compost. 



The efficacious matter contained in a pulverulent 

 manure, spread over a high meadow, will penetrate into 

 the soil only after having been dissolved by rain or dew, 

 and if these media are wanting they will remain ex- 

 posed to the winds and sun. Let us admit that the 

 fertilizing azotous elements are carbonate of ammonia, 



* The natural nitre-beds furnish materials much richer 

 according to John Daivy in the Oura aud Bengal : 



Grains Nitre. 

 The earth extracted from the Cave of Memora 



will contain per kilogramme 31.0 



The earth from the Cave of Oura 68.0 



The nitrate earth from the district of Tirhoot 



(Bengal) 120.0 



It is remarkable that these nitrified earths are taken from the 

 sides of caverns that the Indians scrape in a manner with a 

 kind of small hatchets ; they work thus only on the surface of 

 the rock, where the saltpetre accumulates in efflorescenee. 

 The richness, therefore, as stated, must not be applied to the 

 mass of the earth. 



t In order to convert the weights and volumes indicated 

 in the old memoirr, into present weights and measures, I 

 have taken 38 kilogrammes for the weight of the cubic foot 

 of earth, and 500 grammes for the equivalent of the pound. 



