FARMERS' REGISTER— CARBONACEOUS MOULD— SOIL. 



733 



is re-dissolved in water, its taste is weak, bitter 

 and disagreeable. Caustic ammonia gives a like 

 mass, soluble in water, which gives up, during 

 evaporation, the excess of alkali employed. Geine 

 is not dissolved always in alkaline carbonates; 

 when it is so dissolved, these carbonates are trans- 

 formed, half into geates, half into bi-carbonates. 

 When the solulion is boiled, the bi-carbonate is 

 decomposed with disengagement of carbonic acid 

 pas, and in this manner the geine drives oil' all 

 the carbonic acid. If a solution of geine in car- 

 bonate of ammonia, is evaporated, a residue is 

 obtained containing neutralized geate of ammonia. 

 The solution of geine in caustic j)otash in excess, 

 absorbs oxygen from the air, and at the end oi' 

 some time, the alkali is in part carbonated. 



Geine forms with the alkaline earths pulverulent 

 combinations but little soluble, which have an ex- 

 ternal resemblance to geine. The best means lor 

 obtaining them, is to mix a solution of the geate 

 of ammonia, with the solution of an earthy salt; 

 the combination of the geine with the earth is pre- 

 cipitated, and may be separated by fdtration, Irom 

 the supernatant fluid. In the humid state, these 

 compounds are slightly soluble in water. Accord- 

 ing to the experiments of Sprengel, one part of 

 geate of barytes is dissolved in 5200 parts of water, 

 one part of geate of lime is soluble in 2000 parts of 

 water, and one part of geate of magnesia, in 160 

 parts of water, cold. These same compounds rc- 

 fjuire for their solution, rather smaller proportions 

 of boiling water. Atler having been completely 

 dried, they will no more dissolve. In the air, the 

 base is combined in part with carbonic acid, and 

 the carbonate which results thereti-om, remains in 

 the state of mixture with a combination of geine, 

 and of a base analogous to a super-salt. The 

 alkaline carbonates decompose the earthy geates; 

 they dissolve the geine, and leave the base in the 

 state of carbonate. According to Sprengel, the 

 geates of lime and magnesia are dissolved in the 

 caustic fixed alkalis, and in the carbonate of am- 

 monia. Other chemists have not arrived at the 

 same result; and according to them, the geate of 

 potash, acted on by the hydrate of lime, precipi- 

 tates all the geine. The geate of alumina is pre- 

 cipitated when a solution of alum is mixed with a 

 solution of geate of potash, or of ammonia. This 

 compound is dissolved in 4200 parts of cold water. 

 In the moist state it is dissolved easily, and in abun- 

 -dance, in the alkaline carbonates and hydrates, 

 and even in ammonia. According to Sprengel, it 

 resists the decomposing action of acids, so that it 

 if! difficult to extract from it geine exempt from 

 alumine. A combination is obtained having an 

 excess of alumine, by digesting a solution of the 

 geate of ammonia with liydrale of alumina. * 

 " * * * * # * 



Carbonaceous mould. 



The substance to which this name has been 



f riven has been but little examined. It is inso- 

 uble in alkaline liquors. Its color is a brown, 

 almost black. Placed in contact with a body 

 in combustion, it takes fire, and burns with- 

 out flame like spunk. According to the experi- 

 ments of Th. de Saussure, carbonaceous mould 

 combines with the oxygen of the air, and forms ' 

 carbonic acid gas, and when it is left, a long time 

 exposed to air and Avater, it becomes by slow de- 

 grees soluble in alkalis. The acids precipitate it 



i from the alkaline solution, in the Btate of acid 

 {geine. When cold, the sulplmric acid has but 

 little effect on it. According to Bracannot, the 

 nitric acid converts it, at a gentle heat, to a brown 

 liquor, in which water produces a ])recipitate of a 

 chocolate color, Avhich possesses the properties of 

 acid geine, and is dissolved without residue, in the 

 alkaUs. 



Soil [tcrre vegetale.J 



It is the mixture of these several substances 

 with the upper layer of the surface of the earth, 

 which constitutes the vegetable earth, or soil, pro- 

 perly so called. Arable land is a bed of this soil, 

 placed upon a bed of earth which contains no 

 mould. Its fertility depends upon the quantity of 

 mould which it contains. Growing plants con- 

 tinually diminish the quantity of geme contained 

 in the soil; and when the plants are carried off" 

 from the soil on which they grew, which hapj.ens 

 almost always with cultivated land, it is finally 

 exhausted to that degree as to produce nothing. 

 It is on this account that it is necessary to manure 

 land. The matters discharged and left by animals, 

 or the barn-yard manure which is used for this 

 purpose, are by degrees converted into geine, and 

 thus replace the matters dissipated by vegetation. 

 Botanists who have directed their attention to ve- 

 getable physiology, have remarked that the plants 

 vegetate well enough without geine, until the 

 time arrives lor them to commence their sexual 

 functions. But as soon as these are ended, and 

 the fruit begins to be developed, the plants absorb 

 a great quantity of the nutritive principles con- 

 tained in the soil, and if these are not in the soil, 

 the flower falls without forming any fruit. The 

 experiments to Avhich Th. de Saussure has sub- 

 mitted soil, [terre vegetale] appear to demonstrate 

 that the three constituent principles of mould, may 

 be converted the one to the other, under the 

 alternately preponderating influence of air and 

 water. Water converts to the extract of mould a 

 part of the insoluble geine contained in the soil, and 

 this, transformation extends more and more, so 

 that finally the greater part of the geine becomes 

 soluble. In contact with the air, the dissolved 

 matter passes again to the state of geine. The 

 carbonaceous mould which changes a part of the 

 air into carbonic acid, is itself changed by air into 

 geine, and into the extract of mould, and it is upon 

 this transformation that appear to depend in part 

 the advantages derived from the tillage of the soil, 

 which is divided by the action of the plough, and 

 exposed to the immediate influence of the air. In 

 this manner all the parts of the soil contribute to 

 nutrition; whilst it is probable that the solution of 

 the extract of mould, that of the geate of lime, 

 and perhaps also that of the geate of alumine, are 

 immediately absorbed by the roots. During a 

 heavy rain, this solution penetrates the interior, 

 and often to very deep beds of the steril earth; but 

 notwithstanding that, it is not lost to vegetable 

 life: for the roots of trees seek it, and bring it back 

 as matter suitable for their nourishment. 



Experience has demonstrated that quicklime, 

 and the carbonate of lime, mingled with the soil, 

 favor the vegetation produced thereon. Chemistry 

 has not yet explained, in a satisfactory manner, 

 the power which lime thus exerts; however, it is 

 known that when the soil contains this alkaline 

 earth, or, in its place, ashes only, the mould is 



