SOIL. 



proportion oF calcareous matter, the aftion of the muriatic 

 acid, 7, may be omitted. In examining peat foils, he will 

 principally have to attend to the operation by fire and air, 8 ; 

 and in the analyfis of chalks and loams, he will often be able 

 to admit the experiment by fulphuric acid, g. In the firft 

 trials that are made by perfons unacquainted with chemiftry, 

 they mull not expeft much precifion of refult. Many dif- 

 liculties will be met with : but in overcoming them, the mod 

 ufeful kind of praftical knowledge will be obtained, and 

 nothing is fo inftruftive in experimental fcience as the detec- 

 tion of miltakes. The correft analyft ought to be well 

 grounded in chemical information ; but perhaps there is no 

 better mode of gaininec it than that of attempting original 

 inveftigations. In purfuing his experiments, he will be con- 

 tinually obliged to learn from books the hiltory of the fub- 

 ftances he is employing or afting upon ; and his theoretical 

 ideas will be more valuable, in being connefted with pradlical 

 operations, and acquired for the purpofe of difcovery. 



apparatus for the Analyfis of Soils. — The iicceliary appa- 

 ratus and other conveniences for effefting the above purpofes 

 are different : the firll confillsof a retort inconneftion with 

 other veflels, fo as to form a peculiar pneumatic apparatus, 

 by which the quantity of elaltic fluid that is given out during 

 the aiSion of an acid on calcareous foils may be collefted 

 and meafured, the bulk of it being afcertained by the 

 amount of the water that is difplaced. The different parts 

 of the apparatus are thefe. A bottle or retort for receiving 

 and containing the foil ; another containing the acid, furnifh- 

 ed with a ftop-cock ; ?. tube connefted with a flaccid blad- 

 der ; a bottle for containing the bladder ; and a graduated 

 meafure. When this contrivance is ufeJ, a given quantity 

 of foil is introduced into the firlt bottle ; the fecond is filled 

 with muriatic acid, diluted with an equal quantity of water, 

 and the llop-cock being clofed, is connefted with the upper 

 orifice of the firll bottle, wfiich is ground to receive it. 

 The tube connefted with the flaccid bladder is introduced 

 into the lower orifice of the fame bottle, and the bladder, 

 in its flaccid ftatc, placed into the bottle for containing it, 

 which is filled with water. The graduated meafure is put 

 under the tube of the bottle for containing the bladder. 

 When the ftop-cock of the feccnd bottle is turned, the 

 acid flows into the firlt, and afts upon the foil ; the elallic 

 fluid which is generated paffes through the tube connefted 

 with the flaccid bladder into the bladder, and difplaces a 

 quantity of water in the bottle for containing the bladder 

 equal to it in bulk j and this water flows through the tube 

 of the lall bottle into the graduated meafure ; and gives by 

 its volume the indication of the proportion of carbonic acid 

 difengaged from the foil ; for every ounce meafure of which 

 two grains of carbonate of lime may be eftimated or allow- 

 ed, as already fuggelled. 



The other things arc, an Argand's lamp and fland ; fun- 

 nels for the purpofe of filtering ; and bottles for containing 

 the different re-agents, asprevioufly noticed. 



Another method of deciding in regard to the nature, 

 properties, and qualities of foils, but which is far inferior 

 to that of chemical analyfis, though moll frequently had 

 recourfe to in purchafing of land, is that of attending to 

 the growth and colour of the vegetables which grow upon or 

 cover it ; but it requires a found judgment, mucli experience, 

 and a correft eye in the execution. 



It is cuflomary, alfo, for farmers to have recourfe to other 

 marks in forming their judgments of foils, fuch as their ap- 

 pearances or colours, and their adhefion, tenacity, or loofe- 

 nefs and friability. Thus, the ha/.el-browii Ihews a valu- 

 able fort of loamy foil, and tiie reddifli faiidy mould a good 

 one of the lighter kind. The wetnels of lands fliould lake- 



wife be well confidered, fo far as it is connefted with the na- 

 ture of the foil. From the full confideration of all thefe 

 different circumftances, with a competent experience, a to- 

 lerably correft decifion may in general be formed in refpeft 

 to the nature of land. See Farm. 



Sir Humphrey Davy, in his " Elements of Agricultural 

 Chemillry," confiders it as a vain labour to attempt to clafs 

 foils with fcientific accuracy. He thinks, too, that the dif- 

 tiiiftions at prefent adopted by farmers are quite fufhcient 

 for the purpofes of agriculture ; efpecially if fome degree 

 of precifion be had recourfe to in the application of the 

 terms. The term fandy, he thus conceives, fliould never 

 be applied to any foil that docs not contain at leall feven- 

 eighths of fand ; fandy foils that effervefce with acids, fhould 

 be diilinguifhed by the name of calcareous fandy foil, to dif- 

 tinguifh them from thofe that are filiceous. The term clayey 

 foil fhould not be made ufe of to any land which contains 

 lefs than one-fixth of impalpable earthy matter, not confi- 

 derably effervefcing with acids : the word loam fhould be 

 limited to foils containing at leaft one-third of impalpable 

 earthy matter, copioufly effervefcing with acids. A foil to 

 be confidered as peaty, fhould contain at lead one-half of 

 vegetable earthy matter. And that, in cafes when the 

 earthy part of a foil obvioufly confifts of the decompofed 

 matter of one particular fort of rock, a name derived from 

 the rock may with propriety, it is fuppofed, be given to it. 

 In this way it is imagined, that if a fine red earth be found im- 

 mediately above decompofing bafalt, it may be denominated 

 bafaltic foil. If fragments of quartz and mica be found 

 abundant in the materials of the foil, as is often the cafe, it 

 may be called granitic foil ; and the fame thing may be done 

 in a great number of other fimilar cafes. 



It is evident, that the greater precifion and correftnefs 

 there are in this bufinefs, the greater will be the advantages 

 of the cultivators of the land or foil. 



Dlv'i/ion of Soils. 



Kinds. 



1. Clayey, 



2. Loamy, 



3. Chalky, 



4. Gravelly, 



5. Sandy, 



6. Peaty or mofly, 



7. Boggy and heathy, or 



8. Moory, 



However, thefe fcveral divifions mull evidently be capa- 

 ble of being fubdivided under various other heads, according 

 to the differences in the conftituent ingredients. 



Clayey Soils. — It may be remarked, that as clay is feldom 

 found in any thing near a flate of purity in foils, it is plain 

 that there mufl be much difference in the foils in which it is 

 the chief conftituent principle, according to the proportion 

 and nature of the admixture that has taken place. Thefe 

 fiiils are moflly found to contain an intermixture of different 

 earthy materials, with various animal, vegetable, and mi- 

 neral fubllances, and often blended with confiderable quan- 

 tities of filiceous and fandy matters. It has been obierved, 

 in a late praftical work, on the authority of Dr. Anderfon, 

 that It is upon this account that the clayey foils of fome dif- 

 trifts are fo abundantly fruitful and pioduftive, while thofe 

 of others are infuperably llerile and refraftory. Farmers, or 

 thofe engaged in cultivating land, for the moll part being 

 only acquainted or converfant with earth or mould, as it 

 offers itfelf to their attention in the grofs or whole, have 

 not, lie thinks, been led to remark tiie aflonifhing diverfity 

 that takes place in refpeft to the properties of clays and 



other 



