106 



THE AGRICULTURAL GAZETTE. 



Wheat, on poor clay land. Four ridges were sowru with 

 nitrate when the Wheat was about a foot high; little 



eft'ect was perceptible during its growth, save in a darker 



shade which it assumed, as U common to all crops where 

 nitrate is applied ; and on being cut those ridges produced 

 so few sheaves more than the others, that I was not induced 

 to keep their produce separate; but in the spring of the 

 following year, the new grasses upon them were found to 

 be much better than npoo any others in the field. The 

 pasture was heavily -tooked with ewes and lambs, and eaten 

 bare, the sheep giving those ridges the preference. When 

 the iambs were V eased, the past r • was cleared of stock 

 for a fortnight, when the same thing was repeated; the 

 Grass on those ridges a^ain took considerably the lead of 

 all the rest, and was again preferred by the sheep when 

 they returned to it. Tliis was a result which I had not 

 anticipated, and proves either that the effect of the nitrate 

 continued in operation during the following season, or tha* 

 its effect in the first year upon the grass was such as to 

 nourish and strengthen the plants so much as to cause 

 them to stand better through the winter, and to shoot out 

 much more vigorouoly in the spring. The latter is, I 

 think, the more reasonable conjecture. 



In the begiuuing of May bat, (1841,) I applied nitrate 

 of soda and a mixture of nitrate and manganese to equal 

 quantities of grass of the first year's seeds, intended for 

 mowing, leaving h portion without any dressing. The 

 land was well covered with plants of red and white Clover 

 and R\e Grass, but not of first-rate quality. Both por- 

 tions to which tin; dressings were applied soon assumed 

 a dark appearance and a rapid growth ; the difference was 

 perceptible at any distance from which f he field was visible. 

 The different portions were cut, and the produce of each 

 carefully kept distinct and weighed when made into hay 

 and put up in pikes, of which the following is the result: — 



. No. 1. 

 Description of dressing:. Nitrate of 



No. -'. 



Milanese 



Weight of Hay per acre. 



Value of Hay on eacii 



acre, at :\l. per ton 

 Cost of each top-dressing 



per acre 

 Value of Hay per acre, 



deducting- expense o> 



top-dressings 



i tuns 88 st. 3 tons 2! it. 2 tons 37 >-t. 



j£ 8. d. 

 JO 13 



1 6 



it 



9 



.*. d 



7 Hi 



l i o 



J! s. d. 



6 13 10$ 







9 7 I 8 6 loi I 6 13 loi 



When the aftermath had began t v *..„~v .. r , * « FF „ ou 



the same dressing as above, and al<o a mixture of guano 

 and soil to portions of the land which were left without 

 anything before. The effect as to colour and growth was 

 the same as in the previous experiment, from the nitrate 

 and manganese. That from the guano was less apparent 

 and slower, hut still the growth was greater than where 

 nothing was applied to the grass. One thing was very 

 obvious, that the fctock when put into the field gave a 

 great preference to the portions which had received the 

 saline dressings over that to which guano had been applied, 

 as well as to that which had nothing.— John Grey. DM- 

 ston House. 



{To be continued.) 



REPORT of DR. VON MARTIUS ox GUANO. 



In answer to the summons of the general committee, I 

 have the honour to submit the following report upon the 

 nature of guano, upon its history, and also its utility as 

 a manure in Bavaria. Guano is the excrement of various 

 sea-birds, as the cormorants, flamingoes, cranes, &c. and 

 is found on many little islands off the coast of Peru, 

 situated between 13° and 2 i° south latitude. Its quantitv 

 is so great that it is obtained by means of mining opera'- 

 tions. The word guano belongs to the old Peruvian or 

 Quichna language, and signifies muck, or dung. It is 

 pronounced Huanu by the Peruvians, which the .Spaniards, 

 according to the genius of their language, spell guano. 

 This substance was known to the inhabitants of Peru as a 

 valuable manure long before the possession of their 

 country by the Spaniards ; H nd the success of the culture 

 of the barren sandy tracts of land along the coast depended 

 in a great measure on the use of this substance, so favour- 

 able to vegetation. 



The use of guano as a manure was first mentioned bv 

 Inca Garcilasso de la Vega, a Spaniard who wrote on 

 Peru as early as 1 723, in a work entitled M Commentaries 

 Reales. •• On the sea-coast," savs he, "between Are- 

 quipa and Tarapac*, in a tract of land more than two 

 leagues in length, they have no other kind of manure 

 than that afforded by sea-birds, which dwell in countless 

 numbers on the sea-coast. They lay their eggs on certain 

 islands along the coast, and the quantity of excrement 

 they leave there is astonishingly great. At a distance 

 the masses of excrement look like the tops of a range of 

 hills. At the time the Incas governed Peru the birds 

 were preserved with great care. The punishment of 

 death was decreed against those who landed on the island 

 during breeding-time, or frightened the birds, or at any 

 time destroyed them. Each island was a distinct pro- 

 vince, or, when large, was divided into several provinces 

 over each of which an overseer was appointed by the 

 Incas, whose care it w aB to se<- that every district had its 

 due proportion, and no one defrauded his neighbour of the 

 universally-needed manure." 



Frezier, who travelled In Peru in 1712 to 1711, men- 

 tions having seen in the port of Ariea, and in the island 

 of Iquhiua, the guano dug up by NegrOff* About the 

 same time Feuille also speaks of the pestilential exhala- 

 tions from the guano islands, and of the ships (Gunneros) 

 employed along the coast for its exportation. Ulloa, also, 

 later reported on it iu his great work upon Peru. Al 



ander von Humboldt was the first who brought specimens 

 of gua-io to Europe, which was in 1804. He sent speci- 

 mens for examination to Vauquelin, Fourcroy, and Klap- 

 roth*, and «poke of it himself in the following manner :— - 

 u The guano is deposited in layers 50 or CO feet thick on 

 the granite of many of the South-sea Islands, off the 

 const of Peru. During 300 years the coast-birds have 

 only deposited guano a few lines in thickness. This 

 shews how great must have been the number of birds, 

 and how many centuries must have passed over in order 

 to form the present guano-beds." 



Humboldt put the question to K'aproth as to whether the 

 guano had been deposited on the present islands, or had 

 been thrown up by some convulsion of nature. Although 

 at first sight the simplest explanation appears to be that 

 it was deposited by birds in its present position, yet an 

 objection occurs from the fact that neighbouring islands 

 present no guano. But this objection may be overruled 

 by the well-known fact that birds return always to the 

 same places to nidify, and an analogous phenomenon 

 takes place in those islands which are exclusively sought 

 by turtles for the purpose of lajing their eggs. But be 

 this as it will, the guano ex.ists in such quantities as to 

 give it the importance of a geological formation, and in 

 this respect is the counterpart of those formations which 

 owe their existence to animals, as those formed by species 

 of recent infusoria. 



The guano layers, according to the length of time they 

 have been deposited, have undergone many changes. 

 Here and there they are covered with siliceous sand, and 

 have thus been protected from the influence of the wea- 

 ther. In other place.*, on the other hand, they are open 

 and exposed to the action of light, air, and water, which 

 have effected iu them many decompositions. Such 

 changes are indicated iu most cases by an ochre-yellow 

 guano, resembling Spanish snuff, the colour changing 

 according to the greater or lesser amount of decomposi- 

 tion. Fresh guano h of a white colour, but that which 

 is dug up has a bright or ochre-yellow, brown, or red 

 colour. The chemical composition of guano is very vari- 

 ous ; and this point ehould be attended to where large 

 quantities are bought, a* some sorts are worth nothing 

 like so much as others. 



(To be continued.) 



' X - 



ON MINERAL AND INORGANIC MANURES. 



No. VII. 

 By Professor Charles Spring bl. 



2. Chalk. — Chalk is one ot the most recent lime forma- 

 tions ; and although it consists chiefly of carbonate of 

 lime (lime and acid combined in the same proportion as 

 in the limestones), it contains always more extraneous 

 admixtures than the solid limestone, — so much so, that 

 it often passes into marl. To these admixtures— clay, 

 silica, magnesia, phosphate of lime, common salt, &c.,— » 

 its value as a manuring substance is chiefly owing. If it 

 contains much clay, like marl, it will fall to pieces 

 if lying in the open air, as the marl does ; if it contains 

 much silica it must he burnt first like the lime, else it 

 will not fall to pieces ; but in burning it, too much heat 

 is to be avoided, else a silicate of lime will be produced. 

 At times chalk is so earthy, that it can be easily broken 

 in pieces, and then it may be used without being burnt. 

 In this case, however, it will never manure so well as if 

 it had been burnt, as it will be deficient in caustic proper- 

 ties, and must then be used in large quantities, in order 

 ta produce any striking result. If earthy chalk be burnt, 

 large lumps of it are first baked, and then placed in kilns 

 constructed for that purpose. Whenever fuel is not too 

 expensive, it will always be best to use chalk in a burnt 

 state, especially if a ferruginous, sour, clayey, or peaty soil 

 is to be acted upon. It is true, a clayey soil may be also 

 improved mechanically by unburnt chalk, but then it 

 must not be too stony, and large quantities must be used. 



If chalk is burnt, its effects are similar to that of lime ■ 

 if unburnt, it acts like marl, of which we shall speak pre- 

 sently. Of burnt chalk no more is required, per acre 

 than of burnt lime ; of unburnt, however, the quantity is 

 to be as great, or even greater, than of those marls which 

 are richest in lime. It must be taken into account whether 

 chalk is earthy or stony ; because, as the latter acts but 

 very gradually, a much greater quantity will be required. 

 In meagre, light soils, however, neither earthy nor stony 

 chalk will act beneficially, which might naturally be ex- 

 pected, as these soils are deficient in most substances 

 which plants require for nourishment, and such chalk 

 does not convey to the ground any of those substances 

 except lime. I once saw earthy chalk used with great 

 confidence on a clayey soil not deficient in humus, but 

 the result was so much le?-s than was expected, that the 

 experiment was never repeated. 



3. Marl — which has been used from time immemorial 

 as a manure, is a compound of clay and carbonate of lime. 

 Still, however, chemical analysis proves that most sorts 

 of marl contain more or less of carbonate of magnesia, 

 gypsum, common salt, silicate of potash, silicate of soda' 

 manganese, quartz, and some other substances. These 

 must not be lelt unnoticed, because we shall see presently 

 that it is on these very substances, hitherto not duly taken 

 into account, that the value of marl depends. According 

 to its predominant constituents, it bears the name of lime, 

 magnesia, clay, and sand-marl. 



A characteristic criterion of marl is, that being exposed 

 to air it will fail in pieces, which is caused by the various 

 degrees in which its component parts attract water ; and as 

 different degrees of expansion are thereby produced, it is 



vious , that on becoming successively wet and dry, these 

 parts will separate from each other. 



* l'or the result-, ol the ixaminatiou <>! u.ese olieint-ts see 



I "MernoircaderinstituV' torn. vi. } and Klaproth's "Ueiua'c »• 

 vol. vi. ° ' 



There are .earthy and stony marls. The former i 8 

 mostly found in the diluvial formation, and owes its one' 

 to a most diversified composition of mineral substance* 

 (vide my treatise on soils). Some distinguish also a shell 

 marl, which is mostly composed of decomposed molusca 

 and is to be found mostly in low grounds under a marsh? 

 soil, consequently where, most probably, fresh-water lakes 

 existed at a former period. Under this name, also roa 

 be considered that calcareous earth which near the* se 

 coast underlies marshy localities. 



It is by the carbonate of lime and magnesia contained 

 in marl that the rffervescence is caused which takes place 

 when mineral ac'ds are poured on it, as by these, carboaie 

 acid is driven off, and escapes in the form of gas. J*, 

 colour, at times green, blue, violet, yellow, red, or brown 

 is owing to both oxides of iron (protoxide and oxide) and 

 if the colour of marl be grey, black, or blackish-brown 

 it is owing mostly to an admixture of coal, bitumen or 

 humus. The value of marl, however, as a manure can 

 never be arrived at, either from its colours or the degree of 

 its effervescence with an acid, or by any other external 

 criterion ; this can only be done by chemical analysis 

 because, at times, it is owing to the presence in it of 

 substances existing in very small quantities, and not dis- 

 cernible by outward appearance. It is with marl as with 

 all other manures, it is useful only when it contains 

 substances in which the soil is deficient. If, for instance 

 the soil does not contain enough gypsum, but, with this 

 exception, if it contain all other mineral substances in 

 such proportions as are required for the nourishment of 

 plants, for such a soil, we say, — a marl which contains 

 no gypsum has little or no value. If, on the contrary, 

 a marl contains but lirtle gypsum, it will improve a soil 

 which is entirely deficient of that mineral, even if it 

 contained so little carbonate of lime, that it could 

 hardly claim the name of marl at all. It is the general 

 opinion th;it that marl is best which contains most car- 

 bonate of lime ; but this is fully contradicted by experi- 

 ence, although it cannot be gainsaid, that this is one of 

 the most effective and powerful of its ingredients. That 

 sort of marl, therefore, which may be very valuable for one 

 sort of soil, is valueless for another ; for the chemical 

 constitution of the soil must always betaken into account. 

 It may be generally assumed, that that sort of marl will 

 be best which contains all the substances required for the 

 nourishment of plants in a due proportion, as in this case, 

 even if the soil to be manured should possess some 

 other nutritive substance, it will be improved by the other 

 component parts of the marl. Silica, however, may be 

 excluded from this calculation, as most soils, moors and 

 marshes excepted, contain a sufficient quantity of it. A 

 marl which consists merely of carbonate of lime and clay 

 possesses but four substances which improve vegetation; 

 whilst a marl, which, besides these two component parts, 

 contains also gypsum, common salt, silicate of potash, 

 phosphate of lime, saltpetre, manganese, and magnesia, 

 will yield to the plants twelve different nourishing sub- 

 stances. It is obvious that a marl which contains many 

 nutritive substances of plants must be preferable to one 

 which possesses but few. If, therefore, any marl contains 

 all the mineral substances which the plants require for 

 nourishment, it may be used to advantage on all sorts of 

 soils ; but if, on the contrary, it contains only 4, 5, 6, or 

 7, it will act beneficially only on such soils as are deficient 

 in those ingredients which it contains. An absolutely 

 and a relatively good marl may thus be distinguished, the 

 former being met with but very rarely iu nature, the latter 

 most abundantly. 



(To be continued.) 



ON THE APPLICATION OF CHEMISTRY TO 

 AGRICULTURE UPON RATIONAL 



PRINCIPLES No. VI. 



(Continued from puge Ql.) 

 I will now proceed to treat separately of the two classes 

 of chemical constituents in all plants — Organic and In- 

 organic, the elements of which must iu some form or other 

 be supplied to the plant. 



1. — Of Organic Principles : — 



A — Non-Azotized. 



Represented by 



A Sugar 1 



B Starch ,-Saccharifie group. 

 C Gum J 



D Oil 



E F«t \ Oleaginous group 



F Wax 



B— Azotizcd. 

 Represented by G Vegetable Fibrine "I 



H Aluumen > Albuminous group. 



J Casein ) 



2.— Inorganic Principles \ — 



Are principally Lime 



Silicon 



Muriate of Soda (Salt) 

 Carbonate of Potash or Magnesia 

 Phosphorus 

 Sulphur 

 Iron, 



and the ultimate chemical composition of the 

 will be seen at a glance of the following table. 



above 



who with for further information will readily find it by 

 reference to Turner, or any other elementary work on 



Chemistry. 



if 



e n I Sugar . 



c = ^ starch . , 

 * S I Oil, fat, &c. 



Organic Prixciples. 

 Oxygen. Nitrogen. Carbon. 



Hydrogen 



51 



42 



79 



7 - 

 6 - 



II* - 



100 

 100 

 100 



1 



22 



If, 



55 



100 



. — ' f Albumen 

 § «j { Fibrin* > 

 <~ I Casein ) 



The difference in chemicil composition of the azotized 

 group is so slight, that I have classed them together as 

 identical, which they are, according to the testimony of 



