484 ORGANOLOGY. 



lions of Ibs. of carbon, which, partly by the process of burning, and 

 partly by that of respiration, produce at least half that quantity of car- 

 bonic acid.* 



The Oil-palms (Cocos nucifera and Elais guineensis) grow in sea- 

 sand. The culture of the latter is largely carried on on the West coast 

 of Africa, in moist damp sand, not enriched by manure. Between the 

 years 1821 1830, England alone imported from the coast of Guinea 

 107,118,000 Ibs. of palm oil, and therewith about 76 million Ibs. of car- 

 bon, drawn from a soil which in itself contained no carbon. At present 

 the yearly import is about 33 million Ibs. of oil ; so that the soil upon 

 which the palms grow must, in order to supply the yearly export of oil, 

 deliver about 25 million Ibs. of carbon. 



The banana, however, affords the most striking example of the pro- 

 duction of carbon. It is usual to plant it originally as a slip, upon a 

 moist rich soil, without any manure whatever ; from the time it becomes 

 capable of bearing, it is allowed to produce for twenty years before any 

 new trees are planted, and when at last new shoots are put in, it is not 

 because the old trees cease to bear, but because the plantation is become 

 confused and disorderly, owing to the continual dying away of the old 

 shoots, and the pushing up of new young shoots from the old roots. 

 According to Humboldt, an acre produces about 98,808 Ibs. yearly, 

 which corresponds with about 43,245 Ibs. of dry substance, and at least 

 17,000 Ibs. of carbon ; hence in twenty years such a surface will yield 

 the prodigious quantity of 345,960 Ibs. of carbon. By this, however, the 

 soil is by no means exhausted. The culture has probably been carried 

 on uninterruptedly for a thousand years in the South Sea islands. On 

 the contrary, the soil is constantly rich in humus, and rendered yet 

 more fertile by the continual shedding of the leaves, and the quick pro- 

 cess of putrefaction in those regions. 



It is known how large are the crops of rice produced from the soil on 

 which this vegetable has been long in constant cultivation, and yet that 

 soil is for the most part never enriched with manure, but only watered. 

 According to Darwin, the richest maize harvests are obtained from the 

 interior of Chili and Peru, from the most sterile quicksands, which are 

 never enriched by manure, and where only small streamlets from the 

 Andes supply any water. There are great expanses of sand, which 

 within the last half century have gradually become covered with birches 

 and firs, and which yet discover spots of the original barren quicksand. 

 So far as my information extends, there is no part of the earth where 

 the inhabitants have applied manure to assist the growth of forests. Yet 

 each forest annually yields to us a considerable quantity of carbon in 

 wood, which is converted into carbonic acid by the process of burning. 

 And it is a fact, long known, that the soil of forests becomes annually 

 not impoverished, but, on the contrary, enriched by the decay of its own 

 leaves, and thus has a large amount of the ingredients requisite to the 

 support of vegetation. As an example of this, we may mention the en- 



* The total production of coffee is about 480 mill. Ibs. ; of sugar, 1600 1700 

 mill. Ibs. The carbon is generally reckoned only at 40 per cent. 1650 mill. Ibs. 

 of sugar give 660 mill. Ibs. carbon, half of which is converted into carbonic acid; 3816 

 mill. Ibs. of cane contain 1 1 26 mill. Ibs. of carbon, which is burnt ; the coffee contains 

 192 mill. Ibs. of carbon; so that coffee and sugar together throw into the atmosphere 

 annually about 6043 mill. Ibs. of carbonic acid gas. During nutrition the non-nitro- 

 genous compounds are entirely, and the nitrogenous are partly, converted into car- 

 bonic acid gas. 



