318 



THE FARMER'S MAGAZINE. 



We find, in fact, that the compost and vegetable 

 mould taken in situations sufficiently vBrious, present, 

 notwithstanding, in their constitution, the same active 

 principles, and that the real difference lies only 

 in their properties. Thus it appears that a fertile earth 

 may be represented by compost disseminated with a 

 quantity, more or less strong, of a mineral basis, whether 

 argillaceous, calcareous, or siliceous. If, for example, 

 we add 4 kilogrammes of sand taken from the sand- 

 stone of the Vosges to 1 kilogramme of the market- 

 gardeners' compost near Paris, we shall obtain a mixture 

 approaching in its aspect and composition the vegetable 

 mould of Liebfrauenberg, and differing from it certainly 

 less than the latter differs from the mould of Bische- 

 viller, of which, however, the sandy basis possesses the 

 same nature and origin. 



In one kilogramme there was of 



Grammes. 

 Azote entering into the composition of 



organic matters 2.101 



Ammonia perfectly formed 0.024 



Nitrate, expressed by nitrate of potash. . .. 0.212 



Phosphoric acid 2.560 



Lime 12.600 



Carbon belonging to organic substances . . 19.800 



A happy circumstance has furnished me with an 

 opportunity of extending my investigations to vegetable 

 earths, which M.Le Gendrc Declay, a zealous traveller, 

 had reported on the shores of the Amazons, and ils 

 principal tributaries. The six samples put into my 

 hand represented the compost or ooze of the shores of 

 the Rio Madeira, the Rio Topajo, the Rio Tiombetto, 

 the Rio Cupari, and the Rio Negro, who.se waters unit- 

 ing themselves to those of the Casiquiare, establish the 

 junction of the two greatest rivers of the New World, 

 the Oronoco and the Amazons ; a communication so 

 astonishing that geographers have doubted its reality 

 until the memorable exploration of Alexander von Hum- 

 boldt. 



The Earth from the shores of the Rio Madeira.— 

 Argillaceous ; very plastic ; bluish grey, enclosing 

 debris of radicles ; does not effervesce with acids ; 

 forests ; culture, tobacco and sugar-cane. 



The Earth taken at the embouchure of the Rio 

 Ti'ombetlo in the yl?«azo«s.— Very argillaceous ; a clear 

 brown ; makes no effervescence ; forests ; culture, tro- 

 pical. 



The Earth taken from the embouchure of the Rio 

 Negro in the Amazons.— 'FyxtmshtA by a yellow sand, 

 very loose; alluvium, having its origin in the granitic 

 mountains of Guiana; does not effervesce; a steppe 

 clothed with herbaceous vegetation. 



The Earth taken from the shores of Lake Saracca, 

 near the Ametzon. — MhtMre of clay and sand ; a deep 

 brown, interspersed with debris of roots ; makes no 



effervescence. The deposit forms on the shore a cliff of 

 from 80 to 100 metres thickness. The sample has been 

 taken from land cultivated with tropical plants. 



The Earth from the plateau of Santarem, elevated 

 from 200 to 300 metres above the Amazons. — Mixture 

 of sand and clay, almost black ; abundant debris of 

 vegetable matter, having sometimes the appearance of 

 fossil wood ; makes no effervescence ; soil very fertile ; 

 rich culture of cocoa trees, 



The Earth taken from the shores of the Rio Cupari, 

 at the point of junction with the Rio Topajo, is the 

 most remarkable for its constitution and extraordinary 

 fertility. It forms a bank, one or two metres thick, 

 arising from the superposition of alternate strata of sand 

 and leaves, often well preserved, of a deep brown. It 

 becomes entirely disintegrated, and then the sand is 

 easily separated by the sieve. From 100 parts we 

 took — 



Sand 60 



Decayed leaves . . . . . . 40 



100 



The soil of Cupari must be considered as a deposit of 

 I compost of leaves, the extent and power of which ex- 

 plains at once both the vigorous vegetation and the for- 

 midable insalubrity of that hot and humid locality. 

 This natural compost exhibits the peculiarity of con- 

 taining no trace of nitrates, whilst it is unusually rich in 

 ammonia. 



I have disposed the results of these experiments in a 

 tabular form. In discussing them we cannot refrain 

 from offering this observation — that the soils of Brazil, 

 undoubtedly the most fertile we are acquainted with, are 

 derived from Feldspathic rocks, and contain only a few 

 thousandth parts of lime. 



In a kilogramme of air-dried earth — 



Azote enter 



ing into the 



composition 



of organic 



matters. 



Rio-Mai^eira 



Kio-Trombetlo 



Kio-Negro 



Amazons, near Lake 1 



Saracca / 



Amazons-Santarem.. .. 

 Kio-Cupari (natural 1 



compost) J 



Giamm. 

 1.428 

 1.191 

 0.088 



1.820 



6.490 



6.850 



Ammonia 



well, 

 formed. 



Gramm. 



0.090 

 030 

 0.038 



0.012 



0.083 



0.525 



Nitrate 

 equivalent 



to 

 nitrate of 



potash. 



Gramm. 



0.001 

 0.001 

 0.001 



0.000 



0.011 



0.000 



Rio-Madeira 



Rio-Trombetto 



Rio-Negro 



Amazons, near Lake ' 



Saracca 



Amazonfi-Santarem. . , 

 Rio-Cupari (natural " 



compost) J 



Phosphoric 

 acid. 



Gramm. 

 0.864 



0.792 

 0.176 

 288 

 0.445 



Carbon 



belonging to 



organic 



matter. 



Gramni. 

 9.100 

 5.863 

 5.900 



14,941 



71.585 



129.000 



Lime. 



Gramm. 

 2.032 

 3.696 

 3.301 



4.096 



15.640 



4.408 



It appears from these researches that, in spite of 

 origins, diversity of situation^, on the borders of the 

 Rhine, and in the valley of the Amazons — in soils super- 

 abundantly improved by European cultivation, and in 

 alluviums deposited by the great rivers of the impene- 



