NIPPERS. 



efficacious in wet seasons ; and that in dry 

 seasons it is less useful upon sandy soils than 

 upon greasy clays. There is no doubt but 

 that very excellent composts may be made 

 from night-soil ; and, in fact, several are now 

 prepared in London, on a very bold scale, for 

 the service of the farmer; but the success of 

 these is usually impeded by the preparers pro- 

 fessine that their preparations may be used in 

 quantities much too small. Then, again, one 

 or two patents have been taken out in England 

 for artificial manures, by persons who were 

 evidently very grossly ignorant of what they 

 professed to understand. (Johnson on the Fer- 

 tiliztrs, p. 92.) See FAIIM-YAHD MA>UHE; MA- 



JfUHF.S APPT.ICABtK 1IY THE DdlLLJ UllIXK. 



NIPPERS. A term applied to the four teeth 

 in the fore part of the horse's mouth, two in 

 the upper and two in the lower jaw: they are 

 put forth between the second and third years. 

 Nippers, in farriery, are the pincers which the 

 smiths use in shoeing. 



NITRATES OF POTASH AND SODA. 

 Two salts lately much employed in agricul- 

 ture. The first (nitrate of potash) is known 

 in commerce under the name of saltpetre, and 

 is principally procured from the East Indies, 

 where it is found on the surface of the ground, 

 especially in the district of Tirhiit, in Bengal. 

 It also abounds in Ceylon, Persia, Egypt, and 

 even in Spain; but that which is brought to 

 England comes chiefly from India in an impure 

 state, and contains about 70 per cent, of pure 

 nitre. It, however, varies in quality; but the 

 average loss in the purification is generally 

 about 15 to 20 per cent. Nitre is also formed 

 by artificial composts in various parts of Eu- 

 rope. When pure, nitre is composed of nitric 

 acid 54-15 parts, or 1 equivalent; and potash 

 47-15 parts, or 1 equivalent; or 52-9 per cent. 

 of acid -f 47-1 of alkali = 100. 



Nitrate of soda, which is known as cubic petre, 

 is obtained chiefly from Peru, where it is found 

 in a thick stratum, at an elevation of 3500 feet 

 above the level of the Pacific Ocean. (Dar 

 trm's Researches, p. 443.) It is sold, it seems, at 

 the ship's side on the coast of Peru, at 14s. per 

 cwt. It is composed of nitric acid 62-1 parts, 

 and potash 37-9 parts. 



It is only in modern days that saltpetre has 

 been extensively employed as a fertilizer; for 

 it is not long that the nitre of commerce has 

 been produced in quantities sufficiently large 

 and reasonable to enable the farmer to profita 

 bly use it as a manure. That the knowledge 

 of its enriching qualities, however, is not a 

 modern discovery, is too self-evident to be 

 doubted. Virgil (Georgics, lib. i. v. 193, 195) 

 recommends it to the Italian farmers as an ex- 

 cellent addition to the drejjs of olive oil, to form 

 a steep to cause the seed-grain to swell and 

 vegetate with vigour ; and from his days to 

 our own, hardly an agricultural writer has 

 omitted to notice its powers. The very first 

 English author who wrote upon husbandry, in 

 1532, Sir Anthony Fitzherbert, describes it as 

 having the power to insure to the farmer the 

 most abundant crops. And in 1570, a learned 

 German counsellor, Heresbaschius, in his Trea- 

 tise upon Rural Affairs, describes the use of this 

 salt as not an uncommon dressing in his time 



NITRATES. 



or coleworts. A century afterwards, Evelyn* 

 n his Discourse on Earth, told the farmers ii % 

 nis age that if they could but obtain a plentiful 

 supply of saltpetre, they would "need but little 

 other compost to meliorate their ground." And 

 even Jethro Tull, in the early part of the last 

 century, who denied very zealouslv the neces- 

 sary use of manures of all kinds even Tull 

 placed nitre at the head of his list of those 

 substances which he deemed to be the essential 

 food of plants. 



Saltpetre, therefore, must not be regarded as 

 a modern introduction into agriculture; for it 

 has long been used in limited quantities by 

 previous generations of cultivators, who, like 

 us, were content to notice the effects which it 

 produces, without being able to exactly com- 

 prehend its mode of action. 



It is idle to merely substitute words in ex- 

 planation of unknown effects, and to say that 

 saltpetre is a stimulant, or that it yields nitro- 

 gen to the plant; and there is little evidence 

 of its entering into the composition of any of 

 the more commonly cultivated crops: there is, 

 therefore, but a slight probability of its being 

 a direct food of the plants to which the farmer 

 usually applies it. The only common excep- 

 tion is that of barley, in which a minute por- 

 tion of cubic petre (nitrate of soda) is found 

 to exist. 



But although these nitrates have not been 

 detected in the farmer's crops, yet they are 

 known to exist in many plants, most likely as 

 essential ingredients. Thus saltpetre is found 

 in the common horse-radish, in the nettle, and 

 the sunflower. M. Chevalier discovered it in. 

 the Chenopodium olidum ; M. Vauquelin in the 

 deadly nightshade. Dr. John found it in the 

 Mesembryanthemnm crystallinum; M. Chevreul in 

 woad. The growth of the sunflower is mate- 

 rially promoted by watering it with a weak 

 solution of this salt. It languishes in soils 

 which do not naturally contain it; but when 

 the salt is added to the earth, then it immediately 

 makes its appearance in the plant in the usual 

 proportions. 



And although we are not aware of its exist- 

 ence in the ordinary field-crops, yet still it may 

 beneficially exist in them, and exert a consi- 

 derable influence at certain periods of their 

 growth, although in minute proportions: and, 

 notwithstanding we have no direct evidence 

 of the fact, it is not unlikely that its presence 

 may tend to vary, in the vegetable world, the 

 essentially present combinations of nitrogen, in 

 a way which the skilful investigations of the 

 i chemist have not yet succeeded in tracing. 

 Such researches, however, have already proved 

 that nitrogen (of which, with oxygen, the acid 

 of saltpetre is formed) performs a much more 

 important part in vegetable economy than was 

 I once supposed ; and many facts are already 

 apparent which should encourage us to perse- 

 I vere in the examination. For instance, it has 

 , been observed by the farmer that these two ni- 

 , trates (the base of whose acid is nitrogen) have a 

 very powerful effect in adding to the deep green 

 ; colour of plants. Now, this is precisely the 

 effect produced by other fertilizers, which also 

 contain nitrogen ; such as gelatine, urine, oils, 

 blood, soot, fish, &c. In fact, I am not aware 

 4 n 2 845 



